Showing papers in "Applied Biochemistry and Biotechnology in 2011"

Disruption of Chlorella vulgaris Cells for the Release of Biodiesel-Producing Lipids: A Comparison of Grinding, Ultrasonication, Bead Milling, Enzymatic Lysis, and Microwaves

Abstract: A comparative evaluation of different cell disruption methods for the release of lipids from marine Chlorella vulgaris cells was investigated. The cell growth of C. vulgaris was observed. Lipid concentrations from different disruption methods were determined, and the fatty acid composition of the extracted lipids was analyzed. The results showed that average productivity of C. vulgaris biomass was 208 mg L⁻¹ day⁻¹. The lipid concentrations of C. vulgaris were 5%, 6%, 29%, 15%, 10%, 7%, 22%, 24%, and 18% when using grinding with quartz sand under wet condition, grinding with quartz sand under dehydrated condition, grinding in liquid nitrogen, ultrasonication, bead milling, enzymatic lysis by snailase, enzymatic lysis by lysozyme, enzymatic lysis by cellulose, and microwaves, respectively. The shortest disruption time was 2 min by grinding in liquid nitrogen. The unsaturated and saturated fatty acid contents of C. vulgaris were 71.76% and 28.24%, respectively. The extracted lipids displayed a suitable fatty acid profile for biodiesel [C16:0 (~23%), C16:1 (~23%), and C18:1 (~45%)]. Overall, grinding in liquid nitrogen was identified as the most effective method in terms of disruption efficiency and time.

Theranostic applications of nanomaterials in cancer: drug delivery, image-guided therapy, and multifunctional platforms.

Abstract: Successful cancer management depends on accurate diagnostics along with specific treatment protocols. Current diagnostic techniques need to be improved to provide earlier detection capabilities, and traditional chemotherapy approaches to cancer treatment are limited by lack of specificity and systemic toxicity. This review highlights advances in nanotechnology that have allowed the development of multifunctional platforms for cancer detection, therapy, and monitoring. Nanomaterials can be used as MRI, optical imaging, and photoacoustic imaging contrast agents. When used as drug carriers, nanoformulations can increase tumor exposure to therapeutic agents and result in improved treatment effects by prolonging circulation times, protecting entrapped drugs from degradation, and enhancing tumor uptake through the enhanced permeability and retention effect as well as receptor-mediated endocytosis. Multiple therapeutic agents such as chemotherapy, antiangiogenic, or gene therapy agents can be simultaneously delivered by nanocarriers to tumor sites to enhance the effectiveness of therapy. Additionally, imaging and therapy agents can be co-delivered to provide seamless integration of diagnostics, therapy, and follow-up, and different therapeutic modalities such as chemotherapy and hyperthermia can be co-administered to take advantage of synergistic effects. Liposomes, metallic nanoparticles, polymeric nanoparticles, dendrimers, carbon nanotubes, and quantum dots are examples of nanoformulations that can be used as multifunctional platforms for cancer theranostics. Nanomedicine approaches in cancer have great potential for clinically translatable advances that can positively impact the overall diagnostic and therapeutic process and result in enhanced quality of life for cancer patients. However, a concerted scientific effort is still necessary to fully explore long-term risks, effects, and precautions for safe human use.

Fucoidans from Brown Seaweeds Sargassum hornery, Eclonia cava, Costaria costata: Structural Characteristics and Anticancer Activity

Abstract: Fucoidans were isolated by water extraction and ion-exchange chromatography from brown algae Eclonia cava, Sargassum hornery, and Costaria costata collected near of Korean coasts. The structures of fucoidans were investigated. Fucoidan from E. cava was mixture of sulfated rhamnogalactofucan and galactofucan. Fucoidan from C. costata was a sulfated galactofucan. Fucoidan isolated from S. hornery was separated into three fractions: a homofucan sulfate, a homofucan but without sulfate groups, and a sulfated rhamnofucan. The results clearly showed that fucoidans play an inhibitory role in colony formation in human melanoma and colon cancer cells and may be effective antitumor agents.

Cultivating Chlorella sp. in a Pilot-Scale Photobioreactor Using Centrate Wastewater for Microalgae Biomass Production and Wastewater Nutrient Removal

Abstract: This study is concerned with a novel mass microalgae production system which, for the first time, uses "centrate", a concentrated wastewater stream, to produce microalgal biomass for energy production. Centrate contains a high level of nutrients that support algal growth. The objective of this study was to investigate the growth characteristics of a locally isolated microalgae strain Chlorella sp. in centrate and its ability to remove nutrients from centrate. A pilot-scale photobioreactor (PBR) was constructed at a local wastewater treatment plant. The system was tested under different harvesting rates and exogenous CO(2) levels with the local strain of Chlorella sp. Under low light conditions (25 μmol·m(-2)s(-1)) the system can produce 34.6 and 17.7 g·m(-2)day(-1) biomass in terms of total suspended solids and volatile suspended solids, respectively. At a one fourth harvesting rate, reduction of chemical oxygen demand, total Kjeldahl nitrogen, and soluble total phosphorus were 70%, 61%, and 61%, respectively. The addition of CO(2) to the system did not exhibit a positive effect on biomass productivity or nutrient removal in centrate which is an organic carbon rich medium. The unique PBR system is highly scalable and provides a great opportunity for biomass production coupled with wastewater treatment.

Lipid Production by Culturing Oleaginous Yeast and Algae with Food Waste and Municipal Wastewater in an Integrated Process

Abstract: Food waste and municipal wastewater are promising feedstocks for microbial lipid biofuel production, and corresponding production process is to be developed. In this study, different oleaginous yeast strains were tested to grow in hydrolyzed food waste, and growths of Cryptococcus curvatus, Yarrowia lipolytica, and Rhodotorula glutinis in this condition were at same level as in glucose culture as control. These strains were further tested to grow in municipal primary wastewater. C. curvatus and R. glutinis had higher production than Y. lipolytica in media made from primary wastewater, both with and without glucose supplemented. Finally, a process was tested to grow C. curvatus and R. glutinis in media made from food waste and municipal wastewater, and the effluents from these processes were further treated with yeast culture and phototrophic algae culture; 1.1 g/L C. curvatus and 1.5 g/L R. glutinis biomass were further produced in second-step yeast cultures, as well as 1.53 and 0.58 g/L Chlorella sorokiniana biomass in phototrophic cultures. The residual nitrogen concentrations in final effluents were 33 mg/L and 34 mg/L, respectively, and the residual phosphorus concentrations were 1.5 and 0.6 mg/L, respectively. The lipid contents in the produced biomass were from 18.7% to 28.6%.

Influence of feedstock particle size on lignocellulose conversion--a review.

Abstract: Feedstock particle sizing can impact the economics of cellulosic ethanol commercialization through its effects on conversion yield and energy cost. Past studies demonstrated that particle size influences biomass enzyme digestibility to a limited extent. Physical size reduction was able to increase conversion rates to maximum of ≈50%, whereas chemical modification achieved conversions of >70% regardless of biomass particle size. This suggests that (1) mechanical pretreatment by itself is insufficient to attain economically feasible biomass conversion, and, therefore, (2) necessary particle sizing needs to be determined in the context of thermochemical pretreatment employed for lignocellulose conversion. Studies of thermochemical pretreatments that have taken into account particle size as a factor have exhibited a wide range of maximal sizes (i.e., particle sizes below which no increase in pretreatment effectiveness, measured in terms of the enzymatic conversion resulting from the pretreatment, were observed) from liquid hot water > dilute acid and base pretreatments. Maximal sizes also appeared dependent on feedstock, with herbaceous or grassy biomass exhibiting lower maximal size range ( 3 mm). Such trends, considered alongside the intensive energy requirement of size reduction processes, warrant a more systematic study of particle size effects across different pretreatment technologies and feedstock, as a requisite for optimizing the feedstock supply system.

Applications of Loop-Mediated Isothermal DNA Amplification

Abstract: During the last 10 years, with the development of loop-mediated isothermal amplification (LAMP) method, it has been widely applied in nucleic acid analysis because of its simplicity, rapidity, high efficiency, and outstanding specificity. This method employs a DNA polymerase and a set of four specially designed primers that recognize a total of six distinct sequences on the target DNA. Expensive equipment are not necessary to acquire a high level of precision, and there are fewer preparation steps compared to conventional PCR and real-time PCR assays. This paper briefly summarized the applications of LAMP method in pathogenic microorganisms, genetically modified ingredients, tumor detection, and embryo sex identification.

Effects of radiofrequency electromagnetic wave exposure from cellular phones on the reproductive pattern in male Wistar rats.

Abstract: The present study investigates the effect of free radical formation due to mobile phone exposure and effect on fertility pattern in 70-day-old male Wistar rats (sham exposed and exposed). Exposure took place in Plexiglas cages for 2 h a day for 35 days to mobile phone frequency. The specific absorption rate was estimated to be 0.9 W/kg. An analysis of antioxidant enzymes glutathione peroxidase (P < 0.001) and superoxide dismutase (P < 0.007) showed a decrease, while an increase in catalase (P < 0.005) was observed. Malondialdehyde (P < 0.003) showed an increase and histone kinase (P = 0.006) showed a significant decrease in the exposed group. Micronuclei also show a significant decrease (P < 0.002) in the exposed group. A significant change in sperm cell cycle of G0–G1 (P = 0.042) and G2/M (P = 0.022) were recorded. Generation of free radicals was recorded to be significantly increased (P = 0.035). Our findings on antioxidant, malondialdehyde, histone kinase, micronuclei, and sperm cell cycle are clear indications of an infertility pattern, initiated due to an overproduction of reactive oxygen species. It is concluded that radiofrequency electromagnetic wave from commercially available cell phones might affect the fertilizing potential of spermatozoa.

Converting carbohydrates extracted from marine algae into ethanol using various ethanolic Escherichia coli strains.

Abstract: Marine algae, which make up about 80% of the world’s living organisms, contain many energy sources, such as sugars and lipids. Therefore, the possibility of utilizing structural carbohydrates from marine algae for bioethanol production has been studied. In order to obtain monosaccharides, Undaria pinnatifida, Chlorella vulgaris, and Chlamydomonas reinhardtii were used for the saccharification experiments. The pretreatment was carried out by dilute acid hydrolysis and enzymatic treatment. To find the optimal conditions, experiments were performed at several temperatures, acid concentrations, pH conditions and durations. To test bioethanol production, several ethanolic E. coli W3110 strains, which were developed previously, were used. The maximum yield of bioethanol, 0.4 g ethanol/g biomass, was achieved with pretreated C. vulgaris and E. coli SJL2526, derived from wild-type E. coli W3110 and which includes the adhB, pdc, galP, and glk genes.

Study on the Decreased Sugar Yield in Enzymatic Hydrolysis of Cellulosic Substrate at High Solid Loading

Abstract: Current technology for conversion of biomass to ethanol is an enzyme-based biochemical process. In bioethanol production, achieving high sugar yield at high solid loading in enzymatic hydrolysis step is important from both technical and economic viewpoints. Enzymatic hydrolysis of cellulosic substrates is affected by many parameters, including an unexplained behavior that the glucan digestibility of substrates by cellulase decreased under high solid loadings. A comprehensive study was conducted to investigate this phenomenon by using Spezyme CP and Avicel as model cellulase and cellulose substrate, respectively. The hydrolytic properties of the cellulase under different substrate concentrations at a fixed enzyme-to-substrate ratio were characterized. The results indicate that decreased sugar yield is neither due to the loss of enzyme activity at a high substrate concentration nor due to the higher end-product inhibition. The cellulase adsorption kinetics and isotherm studies indicated that a decline in the binding capacity of cellulase may explain the long-observed but little-understood phenomenon of a lower substrate digestibility with increased substrate concentration. The mechanism how the enzyme adsorption properties changed at high substrate concentration was also discussed in the context of exploring the improvement of the cellulase-binding capacity at high substrate loading.

Development and Characterization of an Environmentally Friendly Process Sequence (Autohydrolysis and Organosolv) for Wheat Straw Delignification

Abstract: The present work describes the delignification of wheat straw through an environmentally friendly process resulting from sequential application of autohydrolysis and organosolv processes. Wheat straw autohydrolysis was performed at 180°C during 30 min with a liquid–solid ratio of 10 (v/w); under these conditions, a solubilization of 44% of the original xylan, with 78% of sugars as xylooligosaccharides of the sum of sugars solubilized in the autohydrolysis liquors generated by the hemicellulose fraction hydrolysis. The corresponding solid fraction enrichment with 63.7% of glucan and 7.55% of residual xylan was treated with a 40% ethanol and 0.1% NaOH aqueous solution at a liquid–solid ratio of 10 (v/w), with the best results obtained at 180°C during 20 min. The highest lignin recovery, measured by acid precipitation of the extracted lignin, was 3.25 g/100 ml. The lignin obtained by precipitation was characterized by FTIR, and the crystallinity indexes from the native cellulose, the cellulose recovered after autohydrolysis, and the cellulose obtained after applying the organosolv process were obtained by X-ray diffraction, returning values of 21.32%, 55.17%, and 53.59%, respectively. Visualization of the fibers was done for all the processing steps using scanning electron microscopy.

Metabolomic Profiling of Serum from Human Pancreatic Cancer Patients Using 1H NMR Spectroscopy and Principal Component Analysis

Abstract: Pancreatic cancer is a malignant tumor with the worst prognosis among all cancers At the time of diagnosis, surgical cure is no longer a feasible option for most patients, thus early detection of pancreatic cancer is crucial for its treatment Metabolomics is a powerful new analytical approach to detect the metabolome of cells, tissue, or biofluids Here, we report the application of (1)H nuclear magnetic resonance (NMR) combined with principal components analysis to discriminate pancreatic cancer patients from healthy controls based on metabolomic profiling of the serum The metabolic analysis revealed significant lower of 3-hydroxybutyrate, 3-hydroxyisovalerate, lactate, and trimethylamine-N-oxide as well as significant higher level of isoleucine, triglyceride, leucine, and creatinine in the serum from pancreatic cancer patients compared to that of healthy controls Our data demonstrate that the subtle differences in metabolite profiles in serum of pancreatic cancer patients and that of healthy subjects as a result of physiological and pathological variations could be identified by NMR-based metabolomics and exploited as metabolic markers for the early detection of pancreatic cancer

Enzymatic Treatment and Detoxification of Acid Orange 7 from Textile Wastewater

Abstract: A crude preparation of horseradish roots was used as a low-purity source of horseradish peroxidase (HRP) in dye decolorization experiments. The technical feasibility of the process was studied in bench scale for enzymatic removal of acid orange 7 (AO7), a synthetic dye. Further studies were carried out to understand the effects of process parameters such as pH value, H(2)O(2) level, concentrations of the synthetic dye, and HRP during enzyme-mediated dye degradation. Experimental data revealed that the concentration of AO7, pH of the aqueous phase, amount of the enzyme, and H(2)O(2) level played significant roles on the overall enzymatic reaction. Polyethylene glycol, as an anti-inactivation of HRP, in various concentrations showed no significant effect on the decolorization. The experimental data of initial reaction rates were fitted using an analytical equation proposed by Michaelis-Menten. The acute toxicity tests using Daphnia magna exhibited that the enzymatic treatment significantly decreased the toxicity of the dye solution.

Dissolution and Delignification of Bamboo Biomass Using Amino Acid-Based Ionic Liquid

Abstract: In the present work, the dissolution of bamboo biomass was tested using a number of ionic liquids synthesized in laboratory. It was observed that one of the synthesized amino acid-based ionic liquids, namely 1-ethyl-3-methylimidazolium glycinate, was capable of dissolving the biomass completely. The dissolved biomass was then regenerated using a reconstitute solvent (acetone/water) and was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results were compared to preconditioned bamboo biomass. The regenerated biomass was found to have a more homogenous macrostructure, which indicates that the crystalline form and structure of its cellulose has changed from type Ι to type ΙΙ during the dissolution and regeneration process.

Nanotechnology: Emerging Tool for Diagnostics and Therapeutics

Abstract: Nanotechnology is an emerging technology which is an amalgamation of different aspects of science and technology that includes disciplines such as electrical engineering, mechanical engineering, biology, physics, chemistry, and material science. It has potential in the fields of information and communication technology, biotechnology, and medicinal technology. It involves manipulating the dimensions of nanoparticles at an atomic scale to make use of its physical and chemical properties. All these properties are responsible for the wide application of nanoparticles in the field of human health care. Promising new technologies based on nanotechnology are being utilized to improve diverse aspects of medical treatments like diagnostics, imaging, and gene and drug delivery. This review summarizes the most promising nanomaterials and their application in human health.

Characterization of a defined cellulolytic and xylanolytic bacterial consortium for bioprocessing of cellulose and hemicelluloses.

Abstract: Diminishing fossil fuel reserve and increasing cost of fossil hydrocarbon products have rekindled worldwide effort on conversion of lignocellloloses (plant biomass) to renewable fuel. Inedible plant materials such as grass, agricultural, and logging residues are abundant renewable natural resources that can be converted to biofuel. In an effort to mimic natural cellulolytic–xylanolytic microbial community in bioprocessing of lignocelluloses, we enriched cellulolytic–xylanolytic microorganisms, purified 19 monocultures and evaluated their cellulolytic–xylanolytic potential. Five selected isolates (DB1, DB2, DB7, DB8, and DB13) were used to compose a defined consortium and characterized by 16S ribosomal RNA gene sequence analysis. Nucleotide sequence blast analysis revealed that DB1, DB2, DB7, DB8, and DB13 were respectively similar to Pseudoxanthomonas byssovorax (99%), Microbacterium oxydans (99%), Bacillus sp. (99%), Ochrobactrum anthropi (98%), and Klebsiella trevisanii (99%). The isolates produced an array of cellulolytic–xylanolytic enzymes (filter paper cellulase, β-glucosidase, xylanase, and β-xylosidase), and significant activities were recorded in 30 min. Isolates DB1 and DB2 displayed the highest filter paper cellulase: 27.83 and 31.22 U mg−1, respectively. The highest β-glucosidase activity (18.07 U mg−1) was detected in the culture of isolate DB1. Isolate DB2 produced the highest xylanase activity (103.05 U mg−1), while the highest β-xylosidase activity (7.72 U mg−1) was observed with DB13. Use of microbial consortium in bioprocessing of lignocelluloses could reduce problems such as incomplete synergistic enzymes, end-product inhibition, adsorption, and requirement for high amounts of enzymes in direct use of enzymes.

Studies on Characterization of Bioflocculant Exopolysaccharide of Azotobacter indicus and Its Potential for Wastewater Treatment

Abstract: Partially characterized bioflocculant exopolysaccharide (EPS) produced from an Azotobacter indicus ATCC 9540 strain reported in our previous study was further characterized, and its flocculant potential was investigated at different pH, temperature, and cations concentrations. Flocculant activity at different concentrations of EPS in the absence of cations was reanalyzed by slight modified flocculant assay. It revealed that flocculant activity increased in a concentration-dependent manner up to a certain limit, with the maximum flocculation of 72% at 500 mgL−1 EPS concentration, even in the absence of cations. At the concentration of 10 mgL−1, CaCl2 showed more significant activity (92%) than AlCl3 and MnSO4. Differential scanning calorimetry study and flocculant assay revealed high temperature stability of EPS up to 97 °C. Molecular weight of the EPS determined by size exclusion chromatography was found to be approximately 2 × 106 kDa. Investigation on flocculation efficacy of the characterized EPS for wastewater treatment of dairy, woolen, starch, and sugar industry suggested it to be effective and stable at wide pH range of 5–10. Wastewater treatment with biopolymer at 500 mgL−1 showed reduction in biochemical oxygen demand (38–80%), chemical oxygen demand (37–79%), and suspended solids (41–68%). This study suggests that Azotobacter polymer has high potential in wastewater treatment as bioflocculant and can be used as a potential alternative to chemical flocculants.

Production of Lipids Containing High Levels of Docosahexaenoic Acid by a Newly Isolated Microalga, Aurantiochytrium sp. KRS101

Abstract: In the present study, a novel oleaginous Thraustochytrid containing a high content of docosahexaenoic acid (DHA) was isolated from a mangrove ecosystem in Malaysia. The strain identified as an Aurantiochytrium sp. by 18S rRNA sequencing and named KRS101 used various carbon and nitrogen sources, indicating metabolic versatility. Optimal culture conditions, thus maximizing cell growth, and high levels of lipid and DHA production, were attained using glucose (60 g l−1) as carbon source, corn steep solid (10 g l−1) as nitrogen source, and sea salt (15 g l−1). The highest biomass, lipid, and DHA production of KRS101 upon fed-batch fermentation were 50.2 g l−1 (16.7 g l−1 day−1), 21.8 g l−1 (44% DCW), and 8.8 g l−1 (40% TFA), respectively. Similar values were obtained when a cheap substrate like molasses, rather than glucose, was used as the carbon source (DCW of 52.44 g l−1, lipid and DHA levels of 20.2 and 8.83 g l−1, respectively), indicating that production of microbial oils containing high levels of DHA can be produced economically when the novel strain is used.

Simultaneous recovery of lipids and proteins by enzymatic hydrolysis of fish industry waste using different commercial proteases.

Abstract: Four different commercial proteases (Protease-P-Amano6, Alcalase®, Protex 7L®, and Neutrase®) were evaluated for recovering lipids and protein simultaneously by hydrolysis. Fungal protease (Protease-P-Amano6) resulted in maximum lipid recovery (74.9%) followed by alcalase (61.7%). Peroxide value (PV; milli-equivalents of oxygen per kilogram) in the oil recovered after hydrolysis was 40.48 compared to 8.7 in lipids from fresh fish viscera. However, addition of tertiary butyl hydroxyl quinine at 200 ppm level maintained the PV of oil recovered by hydrolysis closer to oil from fresh waste. Degree of hydrolysis was the highest in case of fungal protease (49.1%) where neutrase resulted in higher total antioxidant activity (micrograms of ascorbic acid equivalents per milligram protein) of 34.4. Protein hydrolysate prepared using fungal protease had the higher diphenylpicrylhydrazyl radical scavenging activity as compared to those from other enzymes. The results indicate the utility of commercial proteases in providing an ecofriendly and feasible solution for reducing disposal problems associated with fish processing.

Cellulase Production by Streptomyces viridobrunneus SCPE-09 Using Lignocellulosic Biomass as Inducer Substrate

Abstract: An actinomycete strain, isolated from a soil sample under a sugar cane plantation in Brazil and identified as Streptomyces viridobrunneus SCPE-09, was selected as a promising cellulolytic strain, and tested for its ability to produce cellulases from agro-industrial residues. Sugar cane bagasse or wheat bran was tested as carbon source, and corn steep liquor tested as nitrogen source. Different concentrations of carbon and nitrogen were tested using factorial design to identify optimal cellulose production. The results showed that media containing wheat bran 2.0% (w/v) and corn steep liquid 0.19% (w/v) lead to the highest production, 2.0 U mL(-1) of CMCase, obtained on the fifth day of fermentation. The pH and temperature profile showed optimal activity at pH 4.9 and 50°C. As for thermostability, endoglucanases were most tolerant at 50°C, retaining more than 80% of maximal activity even after 2 h of incubation. Zymogram analyses using supernatant from growth under optimized conditions revealed the presence of two CMCase bands with apparent molecular masses of 37 and 119 kDa. The combination of pH tolerance and CMCase production from agro-industrial residues by S. viridobrunneus SCPE-09 offers promise for future bioethanol biotechnologies.

Antioxidant Activity and Protective effect of Banana Peel against Oxidative Hemolysis of Human Erythrocyte at Different Stages of Ripening

Abstract: Phytochemicals such as polyphenols and carotenoids are gaining importance because of their contribution to human health and their multiple biological effects such as antioxidant, antimutagenic, anticarcinogenic, and cytoprotective activities and their therapeutic properties. Banana peel is a major by-product in pulp industry and it contains various bioactive compounds like polyphenols, carotenoids, and others. In the present study, effect of ripening, solvent polarity on the content of bioactive compounds of crude banana peel and the protective effect of peel extracts of unripe, ripe, and leaky ripe banana fruit on hydrogen peroxide-induced hemolysis and their antioxidant capacity were investigated. Banana (Musa paradisica) peel at different stages of ripening (unripe, ripe, leaky ripe) were treated with 70% acetone, which were partitioned in order of polarity with water, ethyl acetate, chloroform (CHCl3), and hexane sequentially. The antioxidant activity of the samples was evaluated by the red cell hemolysis assay, free radical scavenging (1,1-diphenyl-2-picrylhydrazyl free radical elimination) and superoxide dismutase activities. The Folin–Ciocalteu's reagent assay was used to estimate the phenolic content of extracts. The findings of this investigation suggest that the unripe banana peel sample had higher antioxidant potency than ripe and leaky ripe. Further on fractionation, ethyl acetate and water soluble fractions of unripe peel displayed high antioxidant activity than CHCl3 and hexane fraction, respectively. A positive correlation between free radical scavenging capacity and the content of phenolic compound were found in unripe, ripe, and leaky ripe stages of banana peel.

Distribution of Heavy Metal Contents and Chemical Fractions in Anaerobically Digested Manure Slurry

Abstract: Digested slurry samples from twenty-one large-scale anaerobic digestion plants together with intensive pig and dairy farms in Jiangsu Province of China were collected and analyzed for total and dissolved concentrations of Zn, Cu and As, as well as chemical characteristics. The results showed that total concentrations of Zn, Cu and As in digested pig slurries were concentrated to <10, <5 and 0.02-0.1 mg/l, respectively; while <2 and 10-30, <1, and 0.02-0.1 mg/l, respectively, in digested dairy slurries. Lowering the dietary supply of these elements to pig and dairy would be the most effective way to control heavy metal contents in digested manure slurries. Dissolved fractions of Zn, Cu and As accounted for 1-74%, 1-33% and 2-53% of the total concentrations, respectively, in digested pig slurries; and 18-65%, 12-58% and 3-68% in digested dairy slurries. The chemical fractions of heavy metals in digested slurries were not only dependent on the total concentrations of heavy metals in raw manures but also on conditions of digestion and storage. Oxidation pond systems could significantly cripple the total contents of heavy metals in digested slurries, and the removal effect was better in multi-oxidation-pond systems than that in primary-oxidation-pond systems. However, the chemical fractions of heavy metals in digested slurries changed in a complicated manner when stored in oxidation ponds, due to the suspended solid deposition, elements reduction, as well as variations of pH values and oxidation-reduction potential.

Cellulases and Hemicellulases from Endophytic Acremonium Species and Its Application on Sugarcane Bagasse Hydrolysis

Abstract: The aim of this work was to have cellulase activity and hemicellulase activity screenings of endophyte Acremonium species (Acremonium zeae EA0802 and Acremonium sp. EA0810). Both fungi were cultivated in submerged culture (SC) containing L -arabinose, D -xylose, oat spelt xylan, sugarcane bagasse, or corn straw as carbon source. In solid-state fermentation, it was tested as carbon source sugarcane bagasse or corn straw. The highest FPase, endoglucanase, and xylanase activities were produced by Acremonium sp. EA0810 cultivated in SC containing sugarcane bagasse as a carbon source. The highest β-glucosidase activity was produced by Acremonium sp. EA0810 cultivated in SC using D -xylose as carbon source. A. zeae EA0802 has highest α-arabinofuranosidase and α-galactosidase activities in SC using xylan as a carbon source. FPase, endoglucanase, β-glucosidase, and xylanase from Acremonium sp. EA0810 has optimum pH and temperatures of 6.0, 55 °C; 5.0, 70 °C; 4.5, 60 °C; and 6.5, 50 °C, respectively. α-Arabinofuranosidase and α-galactosidase from A. zeae EA0802 has optimum pH and temperatures of 5.0, 60 °C and 4.5, 45 °C, respectively. It was analyzed the application of Acremonium sp. EA0810 to hydrolyze sugarcane bagasse, and it was achieved 63% of conversion into reducing sugar and 42% of conversion into glucose.

Plasma-Assisted Pretreatment of Wheat Straw for Ethanol Production

Abstract: The potential of wheat straw for ethanol production after pretreatment with O3 generated in a plasma at atmospheric pressure and room temperature followed by fermentation was investigated. We found that cellulose and hemicellulose remained unaltered after ozonisation and a subsequent washing step, while lignin was degraded up to 95% by O3. The loss of biomass after washing could be explained by the amount of lignin degraded. The washing water of pretreated samples (0–7 h) was analyzed for potential fermentation inhibitors. Approximately 30 lignin degradation products and a number of simple carboxylic acids and phenolic compounds were found, e.g., vanillic acid, acetic acid, and formic acid. Some components had the highest concentration at the beginning of the ozonisation process (0.5, 1 h), e.g., 4-hydroxybenzladehyde, while the concentration of others increased during the entire pretreatment (0–7 h), e.g., oxalic acid and acetovanillon. Interestingly, washing had no effect on the ethanol production with pretreatment times up to 1 h. Washing improved the glucose availability with pretreatment times of more than 2 h. One hour of ozonisation was found to be optimal for the use of washed and unwashed wheat straw for ethanol production (maximum ethanol yield, 52%). O3 cost estimations were made for the production of ethanol at standard conditions.

Dilute Acid Pretreatment of Corncob for Efficient Sugar Production

Abstract: Aqueous dilute acid pretreatments of corncob were conducted using cylindrical pressure vessels in an oil bath. Pretreatments were conducted in a temperature range of 160–190 °C with acid-solution-to-solid-corncob ratio of 2. The acid concentration (v/v) in the pretreatment solution was varied from 0% to 0.7%, depending on temperature. This gives acid charge on ovendry-weight corncob of 0–2.58%. It was found that optimal pretreatment temperature is between 160 and 170 °C based on total xylose and glucose yields and thermal energy consumption in pretreatment. At 170 °C and acid charge of 2.2% on cob, total glucose yield and xylose recovery were 97% and 75%, respectively, which resulted in an overall monomeric sugar recovery of about 88%. Xylose concentration in the hydrolysate was about 12%, with xylose-to-acetic-acid ratio of 8 and to furan (furfural and hydroxymethylfurfural) of about 15.

Ethanol Production from Cashew Apple Bagasse: Improvement of Enzymatic Hydrolysis by Microwave-Assisted Alkali Pretreatment

Abstract: In this work, the potential of microwave-assisted alkali pretreatment in order to improve the rupture of the recalcitrant structures of the cashew able bagasse (CAB), lignocellulosic by-product in Brazil with no commercial value, is obtained from cashew apple process to juice production, was studied. First, biomass composition of CAB was determined, and the percentage of glucan and lignin was 20.54 ± 0.70% and 33.80 ± 1.30%, respectively. CAB content in terms of cellulose, hemicelluloses, and lignin, 19.21 ± 0.35%, 12.05 ± 0.37%, and 38.11 ± 0.08%, respectively, was also determined. Results showed that, after enzymatic hydrolysis, alkali concentration exerted influence on glucose formation, after pretreatment with 0.2 and 1.0 mo L(-1) of NaOH (372 ± 12 and 355 ± 37 mg g(glucan)(-1) ) when 2% (w/v) of cashew apple bagasse pretreated by microwave-assisted alkali pretreatment (CAB-M) was used. On the other hand, pretreatment time (15-30 min) and microwave power (600-900 W) exerted no significant effect on hydrolysis. On enzymatic hydrolysis step, improvement on solid percentage (16% w/v) and enzyme load (30 FPU g (CAB-M) (-1) ) increased glucose concentration to 15 g L(-1). The fermentation of the hydrolyzate by Saccharomyces cerevesiae resulted in ethanol concentration and productivity of 5.6 g L(-1) and 1.41 g L(-1) h(-1), respectively.

Nitrate as an oxidant in the cathode chamber of a microbial fuel cell for both power generation and nutrient removal purposes.

Abstract: Nitrate ions were used as the oxidant in the cathode chamber of a microbial fuel cell (MFC) to generate electricity from organic compounds with simultaneous nitrate removal. The MFC using nitrate as oxidant could generate a voltage of 111 mV (1,000 Ω) with a plain carbon cathode. The maximum power density achieved was 7.2 mW m−2 with a 470 Ω resistor. Nitrate was reduced from an initial concentration of 49 to 25 mg (NO3−−N) L−1 during 42-day operation. The daily removal rate was 0.57 mg (NO3−–N) L−1 day−1 with a voltage generation of 96 mV. In the presence of Pt catalyst dispersed on cathode, the cell voltage was significantly increased up to 450 mV and the power density was 117.7 mW m−2, which was 16 times higher than the value without Pt catalyst. Significant nitrate removal was also observed with a daily removal rate of 2 mg (NO3−–N) L−1 day−1, which was 3.5 times higher compared with the operation without catalyst. Nitrate was reduced to nitrite and ammonia in the liquid phase at a ratio of 0.6% and 51.8% of the total nitrate amount. These results suggest that nitrate can be successfully used as an oxidant for power generation without aeration and also nitrate removal from water in MFC. However, control of the process would be needed to reduce nitrate to only nitrogen gas, and avoid further reduction to ammonia.

Investigation of biosurfactant-producing indigenous microorganisms that enhance residue oil recovery in an oil reservoir after polymer flooding.

Abstract: Three biosurfactant-producing indigenous microorganisms (XDS1, XDS2, XDS3) were isolated from a petroleum reservoir in the Daqing Oilfield (China) after polymer flooding. Their metabolic, biochemical, and oil-degradation characteristics, as well as their oil displacement in the core were studied. These indigenous microorganisms were identified as short rod bacillus bacteria with white color, round shape, a protruding structure, and a rough surface. Strains have peritrichous flagella, are able to produce endospores, are sporangia, and are clearly swollen and terminal. Bacterial cultures show that the oil-spreading values of the fermentation fluid containing all three strains are more than 4.5 cm (diameter) with an approximate 25 mN/m surface tension. The hydrocarbon degradation rates of each of the three strains exceeded 50%, with the highest achieving 84%. Several oil recovery agents were produced following degradation. At the same time, the heavy components of crude oil were degraded into light components, and their flow characteristics were also improved. The surface tension and viscosity of the crude oil decreased after being treated by the three strains of microorganisms. The core-flooding tests showed that the incremental oil recoveries were 4.89–6.96%. Thus, XDS123 treatment may represent a viable method for microbial-enhanced oil recovery.

Recent Progress on Phospholipases: Different Sources, Assay Methods, Industrial Potential and Pathogenicity

Abstract: Significant studies on phospholipases optimization, characterization, physiological role and industrial potential have been conducted worldwide. Some of them have been directed for biotechnological advances such as gene discovery and functional enhancement by protein engineering. Others reported phospholipases as virulence factor and major cause of pathophysiological effects. A general overview on phospholipase is needed for the identification of new reliable and efficient phospholipase, which would be potentially used in number of industrial and medical applications. Phospholipases catalyse the hydrolysis of one or more ester and phosphodiester bonds of glycerophospholipids. They vary in site of action on phospholipid which can be used industrially for modification/production of new phospholipids. Catalytically active phospholipase mainly use phosphatidylcholine as major substrate, but they can also show specificity with other phospholipids. Several accurate phospholipase assay methods are known, but a rapid and reliable method for high-throughput screening is still a challenge for efficient supply of superior phospholipases and their practical applications. Major application of phospholipase is in industries like oil refinery, health food manufacturing, dairy, cosmetics etc. All types of phospholipases can be involved as virulence factor. They can also be used as diagnostic markers for microbial infection. The importance of phospholipase in virulence is proven and inhibitors of the enzyme can be used as candidate for preventing the associated disease.

Modulation of Triterpene Saponin Production: In Vitro Cultures, Elicitation, and Metabolic Engineering

Abstract: Saponins are secondary metabolites that are widely distributed in the plant kingdom and are often the active components in medicinal herbs. Hence, saponins have a potential for the pharmaceutical industry as antibacterial, virucidal, anti-inflammatory, and anti-leishmanial drugs. However, their commercial application is often hindered because of practical problems, such as low and variable yields and limited availability of natural resources. In vitro cultures provide an alternative to avoid problems associated with field production; they offer a system in which plants are clonally propagated and yield is not affected by environmental changes. Additionally, treatment of in vitro cultures with elicitors such as methyl jasmonate may increase the production of saponins up to six times. In vitro cultures are amenable to metabolic engineering by targeting specific genes to enhance saponin production or drive production towards one specific class of saponins. Hitherto, this approach is not yet fully explored because only a limited number of saponin biosynthesis genes are identified. In this paper, we review recent studies on in vitro cultures of saponin-producing plants. The effect of elicitation on saponin production and saponin biosynthesis genes is discussed. Finally, recent research efforts on metabolic engineering of saponins will also be presented.