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Showing papers in "Applied Biochemistry and Biotechnology in 2016"


Journal ArticleDOI
TL;DR: The past and present applications of l-asparaginase are explored, the methods of its production through the solid state and submerged fermentation, purification, and characterization as well as its biological roles are discussed.
Abstract: L-asparaginase (LA) catalyzes the degradation of asparagine, an essential amino acid for leukemic cells, into ammonia and aspartate. Owing to its ability to inhibit protein biosynthesis in lymphoblasts, LA is used to treat acute lymphoblastic leukemia (ALL). Different isozymes of this enzyme have been isolated from a wide range of organisms, including plants and terrestrial and marine microorganisms. Pieces of information about the three-dimensional structure of L-asparaginase from Escherichia coli and Erwinia sp. have identified residues that are essential for catalytic activity. This review catalogues the major sources of L-asparaginase, the methods of its production through the solid state (SSF) and submerged (SmF) fermentation, purification, and characterization as well as its biological roles. In the same breath, this article explores both the past and present applications of this important enzyme and discusses its future prospects.

186 citations


Journal ArticleDOI
TL;DR: Halotolerant bacteria associated with Psoralea corylifolia L., a luxuriantly growing annual weed in salinity-affected semi-arid regions of western Maharashtra, India were evaluated for their plant growth-promoting activity in wheat and revealed promising results under salinity stress.
Abstract: Halotolerant bacteria associated with Psoralea corylifolia L., a luxuriantly growing annual weed in salinity-affected semi-arid regions of western Maharashtra, India were evaluated for their plant growth-promoting activity in wheat. A total of 79 bacteria associated with different parts viz., root, shoot and nodule endophytes, rhizosphere, rhizoplane, and leaf epiphytes, were isolated and grouped based on their habitat. Twelve bacteria isolated for their potential in plant growth promotion were further selected for in vitro studies. Molecular identification showed the presence of the genera Bacillus, Pantoea, Marinobacterium, Acinetobacter, Enterobacter, Pseudomonas, Rhizobium, and Sinorhizobium (LC027447-53; LC027455; LC027457, LC027459, and LC128410). The phylogenetic studies along with carbon source utilization profiles using the Biolog® indicated the presence of novel species and the in planta studies revealed promising results under salinity stress. Whereas the nodule endophytes had minute plant growth-promoting (PGP) activity, the cell free culture filtrates of these strains enhanced seed germination of wheat (Triticum aestivum L). The maximum vigor index was monitored in isolate Y7 (Enterobacter sp strain NIASMVII). Indole acetic acid (IAA) production by the isolates ranged between 0.22 and 25.58 μg mL-1. This signifies the need of exploration of their individual metabolites for developing next-generation bio-inoculants through co-inoculation with other compatible microbes. This study has potential in utilization of the weed-associated microbiome in terms of alleviation of salinity stress in crop plants.

161 citations


Journal ArticleDOI
TL;DR: Investigation of the relationship among different metabolites showed a strong positive correlation with TPC and TFC, and the moderate drought stress treatment was introduced as the optimum condition to obtain appreciable T PC and T FC, while the highest antioxidant activity was obtained in severe stress condition.
Abstract: The changes in total phenolic content (TPC), total flavonoid content (TFC), proline, malondialdehyde (MDA), H2O2, and antioxidant activity were assessed based on three model systems in three Achillea species (Achillea millefolium, A. nobilis, and A. filipendulina) growing under four irrigation regimes, including 100% FC (field capacity as normal irrigation) 75% FC (low stress), 50% FC (moderate stress), and 25% FC (severe stress) conditions. The highest TPC (47.13 mg tannic acid/g DW) and TFC (20.86 mg quercetin/g W) were obtained in A. filipendulina under moderate and severe stress conditions. In 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the highest and the lowest antioxidant activity was obtained for A. millefolium (70.28%) and A. filipendulina (53.21%), respectively, while in the FTC model system A. nobilis revealed the highest antioxidant activity (1.934) in severe drought condition. In the linoleic model system, the highest antioxidant activity was observed under low drought stress condition in A. nobilis. MDA and H2O2 content were increased due to both low (75% FC) and moderate (50% FC) drought stress, but they were decreased under severe stress condition (25% FC). Furthermore, A. millefolium revealed the lowest H2O2 (4.96 nm/g FW) and MDA content (176.32 μmol/g). Investigation of the relationship among different metabolites showed a strong positive correlation with TPC and TFC. Finally, the moderate drought stress treatment (50% FC) was introduced as the optimum condition to obtain appreciable TPC and TFC,, while the highest antioxidant activity was obtained in severe stress condition (25%FC).

155 citations


Journal ArticleDOI
TL;DR: Various microbial cellulases are reviewed with a focus on their classification with mechanistic aspects of cellulase hydrolytic action, insights into novel approaches for determining cellulase activity, and potential industrial applications of cellulases.
Abstract: Microbial cellulases have been receiving worldwide attention, as they have enormous potential to process the most abundant cellulosic biomass on this planet and transform it into sustainable biofuels and other value added products. The synergistic action of endoglucanases, exoglucanases, and β-glucosidases is required for the depolymerization of cellulose to fermentable sugars for transformation in to useful products using suitable microorganisms. The lack of a better understanding of the mechanisms of individual cellulases and their synergistic actions is the major hurdles yet to be overcome for large-scale commercial applications of cellulases. We have reviewed various microbial cellulases with a focus on their classification with mechanistic aspects of cellulase hydrolytic action, insights into novel approaches for determining cellulase activity, and potential industrial applications of cellulases.

153 citations


Journal ArticleDOI
TL;DR: It was observed that application of the simplified method can generate large errors, especially if the biomass contains a relatively low amount of carbon, when applied to CO2 fixation of microalgae cultures.
Abstract: CO2 biofixation was investigated using tubular bioreactors (15 and 1.5 l) either in the presence of green algae Chlorella vulgaris or Nannochloropsis gaditana. The cultivation was carried out in the following conditions: temperature of 25 °C, inlet-CO2 of 4 and 8 vol%, and artificial light enhancing photosynthesis. Higher biofixation were observed in 8 vol% CO2 concentration for both microalgae cultures than in 4 vol%. Characteristic process parameters such as productivity, CO2 fixation, and kinetic rate coefficient were determined and discussed. Simplified and advanced methods for determination of CO2 fixation were compared. In a simplified method, it is assumed that 1 kg of produced biomass equals 1.88 kg recycled CO2. Advance method is based on empirical results of the present study (formula with carbon content in biomass). It was observed that application of the simplified method can generate large errors, especially if the biomass contains a relatively low amount of carbon. N. gaditana is the recommended species for CO2 removal due to a high biofixation rate—more than 1.7 g/l/day. On day 10 of cultivation, the cell concentration was more than 1.7 × 107 cells/ml. In the case of C. vulgaris, the maximal biofixation rate and cell concentration did not exceed 1.4 g/l/day and 1.3 × 107 cells/ml, respectively.

136 citations


Journal ArticleDOI
TL;DR: This study provides the first evidence of NP effect on callus culture development and production of natural antioxidants in P. vulgaris.
Abstract: Prunella vulgaris L. (P. vulgaris) is an important medicinal plant with a wide range of antiviral properties. Traditionally, it is known as self-heal because of its faster effects on wound healing. It is commonly known as a natural antiseptic due to the presence of various polyphenols. There is lack of research efforts on its propagation and production of bioactive compounds under field and in vitro conditions. In this study, the effects of different ratios (1:2, 1:3, 2:1, and 3:1) of silver (Ag) and gold (Au) nanoparticles (NPs) alone or in combination with naphthalene acetic acid (NAA) were investigated for callus culture development and production of secondary metabolites. The Ag (30 μg l-1), AgAu (1:2), and AgAu (2:1) NPs in combination with NAA (2.0 mg l-1) enhanced callus proliferation (100 %) as compared to the control (95 %). Among the different NPs tested, AuNPs with or without NAA produced higher biomass in log phases (35-42 days) of growth kinetics. Furthermore, AgAu (1:3) and AuNPs alone enhanced total protein content (855 μg-BSAE/mg-fresh weight (FW)), superoxide dismutase (0.54 nM/min/mg-FW), and peroxidase (0.39 nM/min/mg-FW) enzymes in callus cultures. The AgAuNPs (1:3) in combination with NAA induced maximum accumulation of phenolics (TPC 9.57 mg/g-dry weight (DW)) and flavonoid (6.71 mg/g-DW) content. Moreover, AgAuNPs (3:1) without NAA enhanced antioxidant activity (87.85 %). This study provides the first evidence of NP effect on callus culture development and production of natural antioxidants in P. vulgaris.

112 citations


Journal ArticleDOI
TL;DR: This review has a main objective to present an approach of Monascus pigments as a reality to obtaining and application of natural pigments by microorganisms, as to highlight properties that makes this pigment as promising for worldwide industrial applications.
Abstract: Monascus species can produce yellow, orange, and red pigments, depending on the employed cultivation conditions. They are classified as natural pigments and can be applied for coloration of meat, fishes, cheese, beer, and pates, besides their use in inks for printer and dyes for textile, cosmetic, and pharmaceutical industries. These natural pigments also present antimicrobial activity on pathogenic microorganisms and other beneficial effects to the health as antioxidant and anticholesterol activities. Depending on the substrates, the operational conditions (temperature, pH, dissolved oxygen), and fermentation mode (state solid fermentation or submerged fermentation), the production can be directed for one specific color dye. This review has a main objective to present an approach of Monascus pigments as a reality to obtaining and application of natural pigments by microorganisms, as to highlight properties that makes this pigment as promising for worldwide industrial applications.

95 citations


Journal ArticleDOI
TL;DR: Overall, nanovesicles are a new class of bioactive compounds from buffalo milk with high proportion of stable immune miRNAs compared to urine and plasma of same animals.
Abstract: Milk is a natural nutraceutical produced by mammals. The nanovesicles of milk play a role in horizontal gene transfer and confer health-benefits to milk consumers. These nanovesicles contain miRNA, mRNA, and proteins which mediate the intercellular communication. In this work, we isolated and characterized the buffalo milk-derived nanovesicles by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), scanning electron microscopy (SEM), Western probing, and Fourier transform infrared (FTIR) spectroscopy. The DLS data suggested a bimodal size distribution with one mode near 50 nm and the other around 200 nm for the nanovesicles. The NTA and SEM data also supported the size of nanovesicles within a range of 50-200 nm. The FTIR measurements of nanovesicles identified some prominent absorption bands attributable to the proteins (1300-1700 cm(-1), amide A and amide B bands), lipids (2800-3100 cm(-1)), polysaccharides, and nucleic acids (900-1200 cm(-1)). The comparative expression profiles of immune miRNA signatures (miR-15b, miR-21, miR-27b, miR-125b, miR-155, and miR-500) in nanovesicles isolated from milk, serum, and urine revealed that these miRNAs are present abundantly (P < 0.05) in milk-derived nanovesicles. Milk miRNAs (miR-21 and 500) that were also found stable under different household storage conditions indicated that these could be biologically available to milk consumers. Overall, nanovesicles are a new class of bioactive compounds from buffalo milk with high proportion of stable immune miRNAs compared to urine and plasma of same animals.

67 citations


Journal ArticleDOI
TL;DR: The application potential of biosorbents in the development of hybrid technology integrated with membrane processes for water and wastewater treatment in industrial scale is outlined.
Abstract: Heavy metal pollution in water emerges as a severe socio-environmental problem originating primarily from the discharge of industrial wastewater. In view of the toxic, non-biodegradable, and persistent nature of most of the heavy metal ions, remediation of such components becomes an absolute necessity. Biosorption is an emerging tool for bioremediation that has gained momentum for employing low-cost biological materials with effective metal binding capacities. Even though biological materials possess excellent metal adsorption abilities, they show poor mechanical strength and low rigidity. Other disadvantages include solid-liquid separation problems, possible biomass swelling, lower efficiency for regeneration or reuse, and frequent development of high pressure drop in the column mode that limits its applications under real conditions. To improve the biosorption efficiency, biomasses need to be modified with a simple technique for selective/multi-metal adsorption. This review is intended to cover discussion on biomass modification for enhanced biosorption efficiency, mechanism studies using various instrumental/analytical techniques, and future direction for research and development including the fate of spent biosorbent. In most of the previously published researches, difficulty of the process in scaling up has not been addressed. The current article outlines the application potential of biosorbents in the development of hybrid technology integrated with membrane processes for water and wastewater treatment in industrial scale.

67 citations


Journal ArticleDOI
TL;DR: Although the corresponding genes in many phylogenetic groups of microbial species show different levels of diversity in terms of the gene sequence, the organisation of the genes in the genome or on plasmids and the activation mode, some organisms show identical hydrocarbon-degrading genes, probably as a result of horizontal gene transfer between microorganisms.
Abstract: Because of the high diversity of hydrocarbons, degradation of each class of these compounds is activated by a specific enzyme. However, most of other downstream enzymes necessary for complete degradation of hydrocarbons maybe common between different hydrocarbons. The genes encoding proteins for degradation of hydrocarbons, including the proteins required for the uptake of these molecules, the specific enzyme used for the initial activation of the molecules and other necessary degrading enzymes are usually arranged as an operon. Although the corresponding genes in many phylogenetic groups of microbial species show different levels of diversity in terms of the gene sequence, the organisation of the genes in the genome or on plasmids and the activation mode (inductive or constitutive), some organisms show identical hydrocarbon-degrading genes, probably as a result of horizontal gene transfer between microorganisms.

66 citations


Journal ArticleDOI
TL;DR: The effects of nitrogen (N) and/or phosphorus (P) starvation on the biochemical composition of native microalgae Chlorella spp. polyculture obtained from the phycoremediation of swine wastewaters were investigated as mentioned in this paper.
Abstract: The effects of nitrogen (N) and/or phosphorus (P) starvation on the biochemical composition of native microalgae Chlorella spp. polyculture obtained from the phycoremediation of swine wastewaters were investigated. Microalgae-specific growth rate of 1.2 day(-1) was achieved (30.3 mg L(-1) day(-1)). PO4 (-2) and NH3 were completely removed from swine digestate effluent after 3 and 11 days, respectively. Microalgae harvested immediately after nutrient removal showed high protein (56-59 %) and carbohydrate (25-34 %) but low lipid (1.8-3 %) contents. Depletion of N or P alone stimulated carbohydrate production at the expenses of proteins. Significant lipid accumulation from 3 % ± 0.5 to 16.3 % ± 0.8 was reached only after 25 days following N and P starvation as demonstrated by Nile red-stained cells. Regarding to the effects of harvesting methods on cellular biochemical composition, circumstantial evidences indicate that coagulation-flocculation with tannin may lead to lower protein and lipid amounts but increased carbohydrate content (p < 0.01) as compared to centrifugation.

Journal ArticleDOI
TL;DR: The aerobic denitrification of reducing NO3− to N2 by strain HNR was demonstrated and the findings show that E. cloacae strain H NR has a potential application on wastewater treatment to achieve nitrate removal under aerobic conditions.
Abstract: A novel aerobic denitrifier strain HNR, isolated from activated sludge, was identified as Enterobacter cloacae by16S rRNA sequencing analysis. Glucose was considered as the most favorable C-source for strain HNR. The logistic equation well described the bacterial growth, yielding a maximum growth rate (μmax) of 0.283 h(-1) with an initial NO3 (-)-N concentration of 110 mg/L. Almost all NO3 (-)-N was removed aerobically within 30 h with an average removal rate of 4.58 mg N L(-1) h(-1). Nitrogen balance analysis revealed that proximately 70.8 % of NO3 (-)-N was removed as gas products and only 20.7 % was transformed into biomass. GC-MS result indicates that N2 was the end product of aerobic denitrification. The enzyme activities of nitrate reductase and nitrite reductase, which are related to the process of aerobic denitrification, were 0.0688 and 0.0054 U/mg protein, respectively. Thus, the aerobic denitrification of reducing NO3 (-) to N2 by strain HNR was demonstrated. The optimal conditions for nitrate removal were C/N ratio 13, pH value 8, shaking speed 127 rpm and temperature 30 °C. These findings show that E. cloacae strain HNR has a potential application on wastewater treatment to achieve nitrate removal under aerobic conditions.

Journal ArticleDOI
TL;DR: Pseudomonas aeruginosa strain, SR17, was isolated from hydrocarbon-contaminated soil that could efficiently utilize paneer whey for rhamnolipid production and reduce surface tension of the medium from 52 to 26.5 mN/m.
Abstract: The present study aimed at isolating rhamnolipid biosurfactant-producing bacteria that could utilize paneer whey, an abundant waste source as sole medium for the production purpose. Pseudomonas aeruginosa strain, SR17, was isolated from hydrocarbon-contaminated soil that could efficiently utilize paneer whey for rhamnolipid production and reduce surface tension of the medium from 52 to 26.5 mN/m. The yield of biosurfactant obtained was 2.7 g/l, upgraded to 4.8 g/l when supplemented with 2 % glucose and mineral salts. Biochemical, FTIR, and LC-MS analysis revealed that extracted biosurfactant is a combination of both mono and di-rhamnolipid congeners. The critical micelle concentration (CMC) was measured to be 110 mg/l. Emulsification activity of the biosurfactant against n-hexadecane, olive oil, kerosene, diesel oil, engine oil, and crude oil were found to be 83, 88, 81, 92, 86, and 100 %, respectively. The rhamnolipid was detected to be non-toxic against mouse fibroblastic cell line L292.

Journal ArticleDOI
Caoxing Huang1, Juan He1, Douyong Min1, Chenhuan Lai1, Qiang Yong1 
TL;DR: It is suggested that the higher nonproductive cellulase adsorption and physicochemical properties of residual lignin in acid-pretreated bamboo may be responsible for its disappointingly low enzymatic digestibility.
Abstract: In this work, to elucidate why the acid-pretreated bamboo shows disappointingly low enzymatic digestibility comparing to the alkali-pretreated bamboo, residual lignins in acid-pretreated and kraft pulped bamboo were isolated and analyzed by adsorption isotherm to evaluate their extents of nonproductive enzyme adsorption. Meanwhile, physicochemical properties of the isolated lignins were analyzed and a relationship was established with non-productive adsorption. Results showed that the adsorption affinity and binding strength of cellulase on acid-pretreated bamboo lignin (MWLa) was significantly higher than that on residual lignin in pulped bamboo (MWLp). The maximum adsorption capacity of cellulase on MWLp was 129.49 mg/g lignin, which was lower than that on MWLa (160.25 mg/g lignin). When isolated lignins were added into the Avicel hydrolysis solution, the inhibitory effect on enzymatic hydrolysis efficiency of MWLa was found to be considerably stronger than that with MWLp. The cellulase adsorption on isolated lignins was correlated positively with hydrophobicity, phenolic hydroxyl group, and degree of condensation but negatively with surface charges and aliphatic hydroxyl group. These results suggest that the higher nonproductive cellulase adsorption and physicochemical properties of residual lignin in acid-pretreated bamboo may be responsible for its disappointingly low enzymatic digestibility.

Journal ArticleDOI
TL;DR: Equal class ranking, neighbor-joining cluster analysis, and principal component analysis (PCA) identified Talwari, Jaberkhet, Manjkhali, and Khirshu populations as promising sources with higher phytochemicals and antioxidant activity.
Abstract: The changes in total phenolics, flavonoids, tannins, valerenic acid, and antioxidant activity were assessed in 25 populations of Valeriana jatamansi sampled from 1200 to 2775 m asl and four habitat types of Uttarakhand, West Himalaya. Significant (p < 0.05) variations in total phenolics, flavonoids, valerenic acid, and antioxidant activity in aerial and root portions and across the populations were observed. Antioxidant activity measured by three in vitro antioxidant assays, i.e., 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic) (ABTS) radical scavenging, 2,2′-diphenyl-1-picryylhydrazyl (DPPH) free radical scavenging, and ferric-reducing antioxidant power (FRAP) assays, showed significant (p < 0.05) differences across the populations. However, no clear pattern was found in phytochemicals across the altitudinal range. Among habitat types, (pine, oak, mixed forest, and grassy land), variation in phytochemical content and antioxidant activity were observed. Equal class ranking, neighbor-joining cluster analysis, and principal component analysis (PCA) identified Talwari, Jaberkhet, Manjkhali, and Khirshu populations as promising sources with higher phytochemicals and antioxidant activity. The results recommended that the identified populations with higher value of phytochemicals and antioxidants can be utilized for mass multiplication and breeding program to meet the domestic as well as commercial demand.

Journal ArticleDOI
TL;DR: This review will give an insight into the selection of drugs in different applications as their properties get modified by interaction with bile salts, thus influencing their solution behavior which, in turn, modifies the phase-forming behavior, microemulsion, and clouding phenomenon, besides solubilization.
Abstract: In this review, bile salt, bile salt–surfactant, and bile salt–drug interactions and their solubilization studies are mainly focused. Usefulness of bile salts in digestion, absorption, and excretion of various compounds and their rare properties in ordering the shape and size of the micelles owing to the presence of hydrophobic and hydrophilic faces are taken into consideration while compiling this review. Bile salts as potential bio-surfactants to solubilize drugs of interest are also highlighted. This review will give an insight into the selection of drugs in different applications as their properties get modified by interaction with bile salts, thus influencing their solution behavior which, in turn, modifies the phase-forming behavior, microemulsion, and clouding phenomenon, besides solubilization. Finally, their future perspectives are taken into consideration to assess their possible uses as bio-surfactants without side effects to human beings.

Journal ArticleDOI
TL;DR: It is promising that L. fermentum SD11 and its bacteriocin may be an alternative approach for promoting oral health or prevention of oral diseases, e.g., dental caries and periodontitis, which would require further clinical trials.
Abstract: Fermencin SD11, a bacteriocin produced by human orally Lactobacillus fermentum SD11, was purified, characterized, and optimized in conditions for bacterial growth and bacteriocin production. Fermencin SD11 was purified using three steps of ammonium sulfate precipitation, gel filtration chromatography, and reverse-phase high-performance liquid chromatography. The molecular weight was found to be 33,000 Da using SDS-PAGE and confirmed as 33,593.4 Da by liquid chromatography-mass spectrometry. Fermencin SD11 exhibited activity against a wide range of oral pathogens including cariogenic and periodontogenic pathogens and Candida. The active activity was stable between 60 - 80 °C in a pH range of 3.0 to 7.0. It was sensitive to proteolytic enzymes (proteinase K and trypsin), but it was not affected by α-amylase, catalase, lysozyme, and saliva. The optimum conditions for growth and bacteriocin production of L. fermentum SD11 were cultured at acidic with pH of 5.0–6.0 at 37 or 40 °C under aerobic or anaerobic conditions for 12 h. It is promising that L. fermentum SD11 and its bacteriocin may be an alternative approach for promoting oral health or prevention of oral diseases, e.g., dental caries and periodontitis, which would require further clinical trials.

Journal ArticleDOI
TL;DR: Results consolidate the candidature of novel freshwater microalgal isolate Scenedesmus sp.
Abstract: This investigation utilized sugarcane bagasse aqueous extract (SBAE), a nontoxic, cost-effective medium to boost triacylglycerol (TAG) accumulation in novel fresh water microalgal isolate Scenedesmus sp. IITRIND2. Maximum lipid productivity of 112 ± 5.2 mg/L/day was recorded in microalgae grown in SBAE compared to modified BBM (26 ± 3 %). Carotenoid to chlorophyll ratio was 12.5 ± 2 % higher than in photoautotrophic control, indicating an increase in photosystem II activity, thereby increasing growth rate. Fatty acid methyl ester (FAME) profile revealed presence of C14:0 (2.29 %), C16:0 (15.99 %), C16:2 (4.05 %), C18:0 (3.41 %), C18:1 (41.55 %), C18:2 (12.41), and C20:0 (1.21 %) as the major fatty acids. Cetane number (64.03), cold filter plugging property (−1.05 °C), and oxidative stability (12.03 h) indicated quality biodiesel abiding by ASTM D6751 and EN 14214 fuel standards. Results consolidate the candidature of novel freshwater microalgal isolate Scenedesmus sp. IITRIND2 cultivated in SBAE, aqueous extract made from copious, agricultural waste sugarcane bagasse to increase the lipid productivity, and could further be utilized for cost-effective biodiesel production.

Journal ArticleDOI
TL;DR: Examination of the feasibility of using magnetic treatment for enhancement of algal lipid production and wastewater treatment in outdoor-cultivated Chlorella pyrenoidosa confirmed that magnetic treatment significantly enhances biomass and lipid productivity of C. pyrenoidsosa.
Abstract: Despite the significant breakthroughs in research on microalgae as a feedstock for biodiesel, its production cost is still much higher than that of fossil diesel. One possible solution to overcome this problem is to optimize algal growth and lipid production in wastewater. The present study examines the feasibility of using magnetic treatment for enhancement of algal lipid production and wastewater treatment in outdoor-cultivated Chlorella pyrenoidosa. Results confirmed that magnetic treatment significantly enhances biomass and lipid productivity of C. pyrenoidosa by 12 and 10 %, respectively. Application of magnetic field in a semi-continuous culture resulted in highly treated wastewater with total nitrogen maintained under 15 mg L-1, ammonia nitrogen below 5 mg L-1, total phosphorus less than 0.5 mg L-1, and CODCr less than 50 mg L-1. In addition, magnetic treatment resulted in a decrease of wastewater turbidity, an increase of bacterial numbers, and an increase of active oxygen in wastewater which might be attributed to the enhancement of growth and lipid production of C. pyrenoidosa.

Journal ArticleDOI
TL;DR: H. erinaceus demonstrated the potential to detoxify OMW and bioconvert OLPR into high-quality biomass, and hence, this fungus could be successfully exploited for the treatment of such by-products.
Abstract: Environmentally acceptable disposal of olive cultivation residues (e.g., olive prunings; olive pruning residues (OLPR)) and olive mill wastes is of paramount importance since they are generated in huge quantities within a short time. Moreover, olive mill wastewater (OMW) or sludge-like effluents ("alperujo"; two-phase olive mill waste (TPOMW)) are highly biotoxic. Hericium erinaceus is a white-rot fungus which produces choice edible mushrooms on substrates rich in lignocellulosics, and its suitability for the treatment of olive by-products was examined for the first time. Fungal growth resulted in a notable reduction of OMW's pollution parameters (i.e., 65 % decolorization, 47 % total phenolic reduction, and 52 % phytotoxicity decrease) and correlated with laccase and manganese peroxidase activities. Solid-state fermentation of various mixtures of OLPR, TPOMW, and beech sawdust (control) by H. erinaceus qualified OLPR in subsequent cultivation experiments, where it exhibited high mushroom yields and biological efficiency (31 %). Analyses of proximate composition and bioactive compound content revealed that mushrooms deriving from OLPR substrates showed significantly higher crude fat, total glucan, β-glucan, total phenolics, and ferric-reducing antioxidant potential values than the control. H. erinaceus demonstrated the potential to detoxify OMW and bioconvert OLPR into high-quality biomass, and hence, this fungus could be successfully exploited for the treatment of such by-products.

Journal ArticleDOI
TL;DR: Bacteria granules performed better during anaerobic digestion of untreated feathers, resulting in approximately two times more methane yield, and Pretreatment improved methane yield by 292 and 105 % when sludge and granules were used on the hydrolysate.
Abstract: Chicken feathers are available in large quantities around the world causing environmental challenges. The feathers are composed of keratin that is a recalcitrant protein and is hard to degrade. In this work, chicken feathers were aerobically pretreated for 2–8 days at total solid concentrations of 5, 10, and 20 % by Bacillus sp. C4, a bacterium that produces both α- and β-keratinases. Then, the liquid fraction (feather hydrolysate) as well as the total broth (liquid and solid fraction of pretreated feathers) was used as substrates for biogas production using anaerobic sludge or bacteria granules as inoculum. The biological pretreatment of feather waste was productive; about 75 % of feather was converted to soluble crude protein after 8 days of degradation at initial feather concentration of 5 %. Bacteria granules performed better during anaerobic digestion of untreated feathers, resulting in approximately two times more methane yield (i.e., 199 mlCH4/gVS compared to 105 mlCH4/gVS when sludge was used). Pretreatment improved methane yield by 292 and 105 % when sludge and granules were used on the hydrolysate. Bacteria granules worked effectively on the total broth, yielded 445 mlCH4/gVS methane, which is 124 % more than that obtained with the same type of inoculum from untreated feather.

Journal ArticleDOI
TL;DR: Positive correlation of 2AP with 2-pentylfuran, 6-methyl-5-hepten-2-one, and (E)-2-nonenal suggests their major role as aroma contributors, and among quantified 26 volatiles, 14 odor-active compounds distinguished vegetative and mature stage.
Abstract: Aroma volatiles in Basmati-370, Ambemohar-157 (non-basmati scented), and IR-64 (non-scented) rice cultivars were qualitatively and quantitatively analyzed at vegetative and maturity stages to study their differential accumulation using headspace solid-phase microextraction, followed by gas chromatography mass spectrometry (HS-SPME-GCMS) with selected ion monitoring (SIM) approach. In addition, expression analysis of major aroma volatile 2-acetyl-1-pyrroline (2AP)-related genes, betaine aldehyde dehydrogenase 2 (badh2) and Δ(1)-pyrolline-5-carboxylic acid synthetase (P5CS), were studied by real-time PCR. Maximum number of volatiles recorded at vegetative (72-58) than at mature stage (54-39). Twenty new compounds (12 in scented and 8 in both) were reported in rice. N-containing aromatic compounds were major distinguishing class separating scented from non-scented. Among quantified 26 volatiles, 14 odor-active compounds distinguished vegetative and mature stage. Limit of detection (LOD) and limit of quantification (LOQ) for 2AP was 0.001 mg/kg of 2AP and 0.01 g of rice, respectively. 2AP accumulation in mature grains was found three times more than in leaves of scented rice. Positive correlation of 2AP with 2-pentylfuran, 6-methyl-5-hepten-2-one, and (E)-2-nonenal suggests their major role as aroma contributors. The badh2 expression was inversely and P5CS expression was positively correlated with 2AP accumulation in scented over non-scented cultivar.

Journal ArticleDOI
TL;DR: A new two-stage cultivation method to maximize the quantitative content and purity of phycocyanin obtained from Spirulina platensis using red and blue light-emitting diodes (LEDs) under different light intensities is proposed.
Abstract: Phycocyanin is a photosynthetic pigment found in photosynthetic cyanobacteria, cryptophytes, and red algae. In general, production of phycocyanin depends mainly on the light conditions during the cultivation period, and purification of phycocyanin requires expensive and complex procedures. In this study, we propose a new two-stage cultivation method to maximize the quantitative content and purity of phycocyanin obtained from Spirulina platensis using red and blue light-emitting diodes (LEDs) under different light intensities. In the first stage, Spirulina was cultured under a combination of red and blue LEDs to obtain the fast growth rate until reaching an absorbance of 1.4–1.6 at 680 nm. Next, blue LEDs were used to enhance the concentration and purity of the phycocyanin in Spirulina. Two weeks of the two-stage cultivation of Spirulina yielded 1.28 mg mL−1 phycocyanin with the purity of 2.7 (OD620/OD280).

Journal ArticleDOI
TL;DR: Pectin was extracted from Indian red pomelo fruit peels and used for the synthesis of cerium oxide nanoparticles (CeO2-NPs), which displayed broad spectrum antimicrobial activity, antioxidant potential, and non-cytotoxic nature.
Abstract: In the present studies, renewable and nontoxic biopolymer, pectin, was extracted from Indian red pomelo fruit peels and used for the synthesis of cerium oxide nanoparticles (CeO2-NPs) having bio-therapeutic potential. The structural information of extracted pectin was investigated by FTIR and NMR spectroscopic techniques. Physicochemical characteristics of this pectin suggested its application in the synthesis of metal oxide nanoparticles. Using this pectin as a template, CeO2-NPs were synthesized by simple, one step and eco-friendly approach. The UV–Vis spectrum of synthesized CeO2-NPs exhibited a characteristic absorption peak at wavelength 345 nm, which can be assigned to its intrinsic band gap (3.59 eV) absorption. Photoluminescence measurements of CeO2-NPs revealed that the broad emission was composed of seven different bands. FTIR analysis ensured involvement of pectin in the formation and stabilization of CeO2-NPs. FT-Raman spectra showed a sharp Raman active mode peak at 461.8 cm−1 due to a symmetrical stretching mode of Ce–O vibration. DLS, FESEM, EDX, and XRD analysis showed that the CeO2-NPs prepared were polydispersed, spherical shaped with a cubic fluorite structure and average particle size ≤40 nm. These CeO2-NPs displayed broad spectrum antimicrobial activity, antioxidant potential, and non-cytotoxic nature.

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TL;DR: This revision covers recent research concerning the various features of bacterial and fungal β-xylosidases with a greater emphasis on their biochemical characteristics and how the genes that encode these enzymes can be better exploited to obtain products of biotechnological interest via the application of different technical approaches.
Abstract: In the present review, we briefly summarize the biotechnological applications of microbial β-xylosidases in the processing of agro-industrial residues into fuels and chemicals and report the importance of using immobilization techniques to study the enzyme. The advantages of utilizing genes that encode β-xylosidases are readily apparent in the bioconversion of abundant, inexpensive, and renewable resources into economically important products, such as xylitol and bioethanol. We highlight recent research characterizing fungal and bacterial β-xylosidases, including the use of classical biochemical methods such as purification, heterologous recombinant protein expression, and metagenomic approaches to discovery β-xylosidases, with focus on enzyme molecular and kinetic properties. In addition, we discuss the relevance of using experimental design optimization methodologies to increase the efficacy of these enzymes for use with residual biomass. Finally, we emphasize more extensively the advances in the regulatory mechanisms governing β-xylosidase gene expression and xylose metabolism in gram-negative and gram-positive bacteria and fungi. Unlike previous reviews, this revision covers recent research concerning the various features of bacterial and fungal β-xylosidases with a greater emphasis on their biochemical characteristics and how the genes that encode these enzymes can be better exploited to obtain products of biotechnological interest via the application of different technical approaches.

Journal ArticleDOI
TL;DR: The unusually higher biomass and the enhanced amount of phenolic compounds as a result of lower amounts of TDZ highlight the importance of this multipotent hormone as elicitor in callus cultures of F. indica.
Abstract: Fagonia indica, a very important anticancer plant, has been less explored for its in vitro potential. This is the first report on thidiazuron (TDZ)-mediated callogenesis and elicitation of commercially important phenolic compounds. Among the five different plant growth regulators tested, TDZ induced comparatively higher fresh biomass, 51.0 g/100 mL and 40.50 g/100 mL for stem and leaf explants, respectively, after 6 weeks of culture time. Maximum total phenolic content (202.8 μg gallic acid equivalent [GAE]/mL for stem-derived callus and 161.3 μg GAE/mL for leaf-derived callus) and total flavonoid content (191.03 μg quercetin equivalent [QE]/mL for stem-derived callus and 164.83 μg QE/mL for leaf-derived callus) were observed in the optimized callus cultures. The high-performance liquid chromatography (HPLC) data indicated higher amounts of commercially important anticancer secondary metabolites such as gallic acid (125.10 ± 5.01 μg/mL), myricetin (32.5 ± 2.05 μg/mL), caffeic acid (12.5 ± 0.52 μg/mL), catechin (9.4 ± 1.2 μg/mL), and apigenin (3.8 ± 0.45 μg/mL). Owing to the greater phenolic content, a better 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity (69.45 % for stem explant and 63.68 % for leaf explant) was observed in optimized calluses. The unusually higher biomass and the enhanced amount of phenolic compounds as a result of lower amounts of TDZ highlight the importance of this multipotent hormone as elicitor in callus cultures of F. indica.

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TL;DR: The results implicate that the isolate BPY5 may be applied for the industrial production of butyrate or the recovery ofbutyrate from lactate-containing wastewater, suggesting that exogenous acetate could enhance lactate conversion at low pH condition.
Abstract: Lactate-utilizing bacteria play important roles in the production of Chinese strong-flavored liquor (CSFL). However, the identity of these bacteria and their lactate-utilizing properties are largely unknown. Here, a lactate-utilizing, butyrate-producing bacterium BPY5 was isolated from an old fermentation pit for CSFL production. The isolate represented a novel species belonging to Clostridium cluster XIVa of family Lachnospiraceae based on phylogenetic analysis using 16S rRNA gene sequences. Strain BPY5 could ferment lactate into butyrate as the major metabolic product. Butyrate was significantly formed at initial lactate concentration from 66 to 104 mM, but substantially declined when initial lactate exceeded 133 mM. At initial lactate concentration of 66 mM, lactate conversion was independent on initial pH from 5.5 to 7.0, but the conversion was completely inhibited when pH dropped below 4.8. Nevertheless, the inhibition on lactate conversion was largely relieved by the addition of acetate, suggesting that exogenous acetate could enhance lactate conversion at low pH condition. Additionally, lactate in CSFL-brewing wastewater was dramatically removed when inoculated with strain BPY5. These results implicate that the isolate may be applied for the industrial production of butyrate or the recovery of butyrate from lactate-containing wastewater.

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TL;DR: Low concentrations of CFS combined with EDTA caused a relevant reduction in already formed biofilms, but this association was not able to eliminate them, and CFSs have the potential to prevent biofilm formation, but they weren't able to destroy already formedBiofilms.
Abstract: The present study aimed to assess the activity of cell-free supernatant (CFS) containing bacteriocins on the formation and maintenance of biofilms developed by Listeria monocytogenes, and the associated effect of bacteriocins and ethylene-diamine-tetra-acetic acid (EDTA) on the formed biofilm. CFS from 9 lactic acid bacteria (LAB) strains was tested for inhibitory activity against 85 L. monocytogenes isolates and 21 LAB strains. Then, 12 L. monocytogenes strains were selected based on genetic profiles and sensitivity to CFS and were subjected to an in vitro assay to assess biofilm formation in microtiter plates, considering different culture media and incubation conditions. Based on these results, 6 L. monocytogenes strains were subjected to the same in vitro procedure to assess biofilm formation, being co-inoculated with CFS. In addition, these strains were subjected to the same in vitro procedure, modified by adding the CFS after biofilm formation. Relevant decrease in biofilm formation was observed in the first experiment, but CFS added after biofilm formation did not eliminate them. CFS from Lactobacillus curvatus ET31 were selected due to its anti-biofilm activity, being associated to EDTA at different concentrations and tested for biofilm control of three strains of L. monocytogenes, using the same in vitro procedure described previously. Concentrated bacteriocin presented poor performance in eliminating formed biofilms, and EDTA concentration presented no evident interference on biofilm elimination. Twelve selected L. monocytogenes strains were positive for investigated virulence makers and negative for luxS gene, recognized as being involved in biofilm formation. Selected L. monocytogenes strains were able to produce biofilms under different conditions. CFSs have the potential to prevent biofilm formation, but they were not able to destroy already formed biofilms. Nevertheless, low concentrations of CFS combined with EDTA caused a relevant reduction in already formed biofilms, but this association was not able to eliminate them. The activity of selected CFS was demonstrated against L. monocytogenes-formed biofilms, being more effective when associated to EDTA at different concentrations.

Journal ArticleDOI
TL;DR: In this article, a total of 21 TB specific aptamers were selected by systematic evolution of ligands by exponential enrichment (SELEX) and two different selection protocols, ultrafiltration and centrifugation, were applied.
Abstract: Tuberculosis (TB) remains to be a major global health problem, with about 9 million new cases and 1.4 million deaths in 2011. For the control of tuberculosis as well as other infectious diseases, WHO recommended “ASSURED” (Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free, and Deliverable to the end user) diagnostic tools that can easily be maintained and used in developing countries. Aptamers are promising tools for developing point-of-care diagnostic assays for TB. In this study, ssDNA aptamers that recognize Mycobacterium tuberculosis H37Ra were selected by systematic evolution of ligands by exponential enrichment (SELEX). For this purpose, two different selection protocols, ultrafiltration and centrifugation, were applied. A total of 21 TB specific aptamers were selected. These aptamers exhibited “G-rich” regions on the 3′ terminus of the aptamers, including a motif of “TGGGG,” “GTGG,” or “CTGG.” Binding capability of selected aptamers were investigated by quantitative PCR and Mtb36 DNA aptamer was found the most specific aptamer to M. tuberculosis H37Ra. The dissociation constant (K d) of Mtb36 aptamer was calculated as 5.09 ± 1.43 nM in 95 % confidence interval. Relative binding ratio of Mtb36 aptamer to M. tuberculosis H37Ra over Mycobacterium bovis and Escherichia coli was also determined about 4 times and 70 times more, respectively. Mtb36 aptamer is highly selective for M. tuberculosis, and it can be used in an aptamer-based biosensor for the detection of M. tuberculosis.

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TL;DR: For the first time, metabolic regulation is proved as a simple and effective way to enhance the output of cordycepin and Cordycepic acid in submerged cultivation of H. sinensis.
Abstract: Hirsutella sinensis is considered as the only correct anamorph of Ophiocordyceps sinensis. To improve cordycepin and cordycepic acid production in H. sinensis, the biosynthetic pathways of cordycepin and cordycepic acid were predicted, and verified by cloning and expressing genes involved in these pathways, respectively. Then, 5′-nucleotidase participating in biosynthetic pathway of cordycepin, hexokinase, and glucose phosphate isomerase involved in biosynthetic pathway of cordycepic acid, were demonstrated playing important roles in the corresponding biosynthetic pathway by real-time PCR, accompanying with significantly up-regulated 15.03-, 5.27-, and 3.94-fold, respectively. Moreover, the metabolic regulation of H. sinensis was performed. As expected, cordycepin production reached 1.09 mg/g when additional substrate of 5′-nucleotidase was 4 mg/mL, resulting in an increase of 201.1 % compared with the control. In the same way, cordycepic acid production reached 26.6 and 23.4 % by adding substrate of hexokinase or glucose phosphate isomerase, leading to a rise of 77.3 and 55.1 %, respectively. To date, this is the first time to improve cordycepin and cordycepic acid production through metabolic regulation based on biosynthetic pathway analysis, and metabolic regulation is proved as a simple and effective way to enhance the output of cordycepin and cordycepic acid in submerged cultivation of H. sinensis.