Showing papers in "Applied Biochemistry and Biotechnology in 2012"

Silver Nanoparticle-Mediated Enhancement in Growth and Antioxidant Status of Brassica juncea

Abstract: Metal nanoparticles can potentially be used as tools for engineering biological redox reactions. Present study underlines the effect of silver metal nanoparticles (at 0, 25, 50, 100, 200 and 400 ppm) on the growth and antioxidant status of 7-day-old Brassica juncea seedlings. Fresh weight, root and shoot length, and vigor index of seedlings is positively affected by silver nanoparticle treatment. It induced a 326 % increase in root length and 133 % increase in vigor index of the treated seedlings. Improved photosynthetic quantum efficiency and higher chlorophyll contents were recorded in leaves of treated seedlings, as compared to the control seedlings. Levels of malondialdehyde and hydrogen peroxide decreased in the treated seedlings. Nanoparticle treatment induced the activities of specific antioxidant enzymes, resulting in reduced reactive oxygen species levels. Decrease in proline content confirmed the improvement in antioxidant status of the treated seedlings. The observed stimulatory affects of silver nanoparticles are found to be dose dependent, with 50 ppm treatment being optimum for eliciting growth response. Present findings, for the first time indicate that silver nanoparticles promote the growth of B. juncea seedlings by modulating their antioxidant status.

Overview of fungal lipase: a review.

Abstract: Lipases (triacylglycerolacyl hydrolases, EC3.1.1.3) are class of enzymes which catalyze the hydrolysis of long-chain triglycerides. In this review paper, an overview regarding the fungal lipase production, purification, and application is discussed. The review describes various industrial applications of lipase in pulp and paper, food, detergent, and textile industries. Some important lipase-producing fungal genera include Aspergillus, Penicillium, Rhizopus, Candida, etc. Current fermentation process techniques such as batch, fed-batch, and continuous mode of lipase production in submerged and solid-state fermentations are discussed in details. The purification of lipase by hydrophobic interaction chromatography is also discussed. The development of mathematical models applied to lipase production is discussed with special emphasis on lipase engineering.

A Potential Commercial Source of Fucoxanthin Extracted from the Microalga Phaeodactylum tricornutum

Abstract: Fucoxanthin, one of the main marine carotenoids, is abundant in macro- and microalgae. Here, fucoxanthin was isolated and structurally identified as the major caroten- oid in the diatom Phaeodactylum tricornutum through chromatographic and spectroscopic methods, such as liquid chromatography-positive-ion atmospheric pressure chemical ioni- zation/mass spectroscopy and nuclear magnetic resonance. This pigment was quantified by reverse-phase high-performance liquid chromatography, and a number of extraction proce- dures were assessed to investigate the effect of solvent type, extraction time, temperature, and extraction method (maceration, ultrasound-assisted extraction, Soxhlet extraction, and pressurized liquid extraction). Among the investigated solvents, ethanol provided the best fucoxanthin extraction yield (15.71 mg/g freeze-dried sample weight). Fucoxanthin content in the extracts produced by the different methods was quite constant (15.42-16.51 mg/g freeze-dried sample weight) but increased steeply based on the percentage of ethanol in water, emphasizing the importance of ethanol in the extraction. The results indicate that P. tricornutum is a rich source of fucoxanthin (at least ten times more abundant than that in macroalgae) that is easily extracted with ethanol, suggesting potential applications in human and animal food, health, and cosmetics.

Current technologies for biological treatment of textile wastewater--a review.

Abstract: The release of colored wastewater represents a serious environmental problem and public health concern. Color removal from textile wastewater has become a big challenge over the last decades, and up to now, there is no single and economically attractive treatment method that can effectively decolorize the wastewater. Effluents from textile manufacturing, dyeing, and finishing processes contain high concentrations of biologically difficult-to-degrade or even inert auxiliaries, chemicals like acids, waxes, fats, salts, binders, thickeners, urea, surfactants, reducing agents, etc. The various chemicals such as biocides and stain repellents used for brightening, sequestering, anticreasing, sizing, softening, and wetting of the yarn or fabric are also present in wastewater. Therefore, the textile wastewater needs environmental friendly, effective treatment process. This paper provides a critical review on the current technology available for decolorization and degradation of textile wastewater and also suggests effective and economically attractive alternatives.

Novel Fungal Pelletization-Assisted Technology for Algae Harvesting and Wastewater Treatment

Abstract: A novel fungi pelletization-assisted bioflocculation technology was developed for efficient algae harvesting and wastewater treatment. Microalga Chlorella vulgaris UMN235 and two locally isolated fungal species Aspergillus sp. UMN F01 and UMN F02 were used to study the effect of various cultural conditions on pelletization process for fungi–algae complex. The results showed that pH was the key factor affecting formation of fungi–algae pellet, and pH could be controlled by adjusting glucose concentration and fungal spore number added. The best pelletization happened when adding 20 g/L glucose and approximately 1.2E8/L spores in BG-11 medium, under which almost 100 % of algal cells were captured onto the pellets with shorter retention time. The fungi–algae pellets can be easily harvested by simple filtration due to its large size (2–5 mm). The filtered fungi–algae pellets were reused as immobilized cells for treatment wastewaters and the nutrient removal rates of 100, 58.85, 89.83, and 62.53 % (for centrate) and 23.23, 44.68, 84.70, and 70.34 % (for diluted swine manure wastewater) for ammonium, total nitrogen, total phosphorus, and chemical oxygen demand, respectively, under both 1- and 2-day cultivations. The novel technology developed is highly promising compared with current algae harvesting and biological wastewater treatment technologies in the literature.

Saliva metabolomics opens door to biomarker discovery, disease diagnosis, and treatment.

Abstract: Metabolomics is the systematic study of the unique chemical fingerprints of low molecular weight endogenous metabolites or metabolite profiles in a biological sample. Metabolites that are important indicators of physiological or pathological states can provide information for the identification of early and differential markers for disease and help to understand its occurrence and progression. Analysis of these key biomarkers has become an important role to monitor the state of biological organisms and is a widely used diagnostic tool for disease. Metabolomic analyses are propelling the field of medical diagnostics forward at unprecedented rates because of its ability to reliably identify metabolites that are at the metabolic level in concentration. These advancements have benefited biomarker research to the point where saliva is now recognized as an excellent diagnostic medium for the detection of disease. Saliva contains a large array of metabolites, many of which can be informative for the detection of diseases. Salivary diagnostics offer an easy, inexpensive, safe, and noninvasive approach for disease detection. Discovery of salivary biomarkers that could be used to scrutinize health and disease surveillance has addressed its diagnostic value for clinical applications. Availability of emerging metabolomic techniques gives optimism that saliva can eventually be placed as a biomedium for clinical diagnostics. Comprehensive salivary metabolome will be an important resource for researchers who are studying metabolite chemistry, especially in the fields of salivary diagnostics, and will be helpful for analyzing and hence identifying corresponding disease-related salivary biomarkers. This review presents an overview of the value of saliva as a credible diagnostic tool, the discovery of salivary biomarkers, and the development of salivary diagnostics now and in the future. In particular, proof of principle has been demonstrated for salivary biomarker research.

Aerobic Granulation: Advances and Challenges

Abstract: Aerobic granulation was developed in overcoming the problem of biomass washout often encountered in activated sludge processes. The novel approach to developing fluffy biosolids into dense and compact granules offers a new dimension for wastewater treatment. Compared with conventional biological flocs, aerobic granules are characterized by well-defined shape and compact buildup, superior biomass retention, enhanced microbial functions, and resilient to toxicity and shock loading. This review provides an up-to-date account on development in aerobic granulation and its applications. Granule characterization, factors affecting granulation, and response of granules to various environmental and operating conditions are discussed. Maintaining granule of adequate structural stability is one of the main challenges for practical applications of aerobic granulation. This paper also reviews recent advances in addressing granule stability and storage for use as inoculums, and as biomass supplement to enhance treatment efficiency. Challenges and future work of aerobic granulation are also outlined.

Biogas production potential and kinetics of microwave and conventional thermal pretreatment of grass.

Abstract: Pretreatment methods play an important role in the improvement of biogas production from the anaerobic digestion of energy grass. In this study, conventional thermal and microwave methods were performed on raw material, namely, Pennisetum hybrid, to analyze the effect of pretreatment on anaerobic digestion by the calculation of performance parameters using Logistic function, modified Gompertz equation, and transference function. Results indicated that thermal pretreatment improved the biogas production of Pennisetum hybrid, whereas microwave method had an adverse effect on the performance. All the models fit the experimental data with R 2 > 0.980, and the Reaction Curve presented the best agreement in the fitting process. Conventional thermal pretreatment showed an increasing effect on maximum production rate and total methane produced, with an improvement of around 7% and 8%, respectively. With regard to microwave pretreatment, maximum production rate and total methane produced decreased by 18% and 12%, respectively.

Effects of light intensity on the growth and lipid accumulation of microalga Scenedesmus sp. 11-1 under nitrogen limitation

Abstract: Scenedesmus spp. have been reported as potential microalgal species used for the lipid production. This study investigated the effects of light intensity (at three levels: 50, 250, and 400 μmol photons m−2 s−1) on the growth and lipid production of Scenedesmus sp. 11-1 under N-limited condition. Carotenoid to chlorophyll ratio was higher when algae 11-1 grew under 250 and 400 μmol photons m−2 s−1 than that under 50 μmol photons m−2 s−1, while protein contents was lower. Highest biomass yield (3.88 g L−1), lipid content (41.1 %), and neutral lipid content (32.9 %) were achieved when algae 11-1 grew at 400 μmol photons m−2 s−1. Lipid production was slight lower at 250 μmol photons m−2 s−1 level compared to 400 μmol photons m−2 s−1. The major fatty acids in the neutral lipid of 11-1 were oleic acid (43–52 %), palmitic acid (24–27 %), and linoleic acid (7–11 %). In addition, polyunsaturated fatty acids had a positive correlation with total lipid production, and monounsaturated fatty acids had a negative one.

Antibiofilm Activity of α-Amylase from Bacillus subtilis S8-18 Against Biofilm Forming Human Bacterial Pathogens

Abstract: The extracellular α-amylase enzyme from Bacillus subtilis S8-18 of marine origin was proved as an antibiofilm agent against methicillin-resistant Staphylococcus aureus (MRSA), a clinical strain isolated from pharyngitis patient, Vibrio cholerae also a clinical isolate from cholera patient and Pseudomonas aeruginosa ATCC10145 The spectrophotometric and microscopic investigations revealed the potential of α-amylase to inhibit biofilm formation in these pathogens At its BIC level, the crude enzyme caused 5181–7307% of biofilm inhibition Beyond the inhibition, the enzyme was also effective in degradation of preformed mature biofilm by disrupting the exopolysaccharide (EPS), an essential component in biofilm architecture Furthermore, the enzyme purified to its homogeneity by chromatographic techniques was also effective in biofilm inhibition (4383–6168%) as well as in degradation of EPS A commercial α-amylase enzyme from B subtilis was also used for comparative purpose Besides, the effect of various enzymes and temperature on the antibiofilm activity of amylase enzymes was also investigated This study, for the first time, proved that α-amylase enzyme alone can be used to inhibit/disrupt the biofilms of V cholerae and MRSA strains and beholds much promise in clinical applications

Biosynthesis of Silver Nanoparticles Using Latex from Few Euphorbian Plants and Their Antimicrobial Potential

Abstract: The synthesis of well-dispersed and ultrafine metal nanoparticles has great interest due to their distinctive physicochemical properties and biomedical applications. This study is the first report of one-step solvent-free synthesis of AgNPs using Euphorbiaceae plant latex. Among evaluated eight latex-producing plants, four (Jatropha curcas, Jatropha gossypifolia, Pedilanthus tithymaloides, and Euphorbia milii) showed high potential to produce physicochemically distinct, small-sized and bactericidal AgNPs. Phytochemical screening showed presence of rich amount of biochemicals in these plants. J. gossypifolia showed uniformly dispersed comparatively small-sized AgNPs. Dose-dependent growth inhibition of bacterial pathogens Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermis, and Micrococcus luteus was observed for J. gossypifolia latex-synthesized AgNPs with minimum inhibitory concentration values 30, 40, 70, 60, and 60 ppm, respectively, after 24 h. Possible mode of action of AgNPs against pathogens was confirmed by analyzing enzymes and cell leakage.

Advances and Developments in Strategies to Improve Strains of Saccharomyces cerevisiae and Processes to Obtain the Lignocellulosic Ethanol-A Review

Abstract: The conversion of biomass into ethanol using fast, cheap, and efficient methodologies to disintegrate and hydrolyse the lignocellulosic biomass is the major challenge of the production of the second-generation ethanol. This revision describes the most relevant advances on the conversion process of lignocellulose materials into ethanol, development of new xylose-fermenting strains of Saccharomyces cerevisiae using classical and modern genetic tools and strategies, elucidation of the expression of some complex industrial phenotypes, tolerance mechanisms of S. cerevisiae to lignocellulosic inhibitors, monitoring and strategies to improve fermentation processes. In the last decade, numerous engineered pentose-fermenting yeasts have been developed using molecular biology tools. The increase in the tolerance of S. cerevisiae to inhibitors is still an important issue to be exploited. As the industrial systems of ethanol production operate under non-sterile conditions, microbial subpopulations are generated, depending on the operational conditions and the levels of contaminants. Among the most critical requirements for production of the second-generation ethanol is the reduction in the levels of toxic by-products of the lignocellulosic hydrolysates and the production of low-cost and efficient cellulosic enzymes. A number of procedures have been established for the conversion of lignocellulosic materials into ethanol, but none of them are completely satisfactory when process time, costs, and efficiency are considered.

Production of oils from acetic acid by the oleaginous yeast Cryptococcus curvatus.

Abstract: The feasibility of the conversion of acetic acid, a metabolite commonly obtained during anaerobic fermentation processes, into oils using the yeast Cryptococcus curvatus was reported. This microorganism exhibited very slow growth rates on acetate as carbon source, which led to design a two-stage cultivation process. The first consisted of cell growth on glucose as carbon source until its complete exhaustion. The second step involved the use of acetate as carbon source under nitrogen limitation in order to induce lipid accumulation. A typical experiment performed in a bioreactor involved a preliminary yeast growth with a glucose initial concentration of 15 g/L glucose. Further additions of acetate and nitrogen source allowed a final lipid accumulation up to 50% (w/w). These promising results demonstrated the suitability of the technique proposed.

Lipids containing polyunsaturated fatty acids synthesized by zygomycetes grown on glycerol.

Abstract: Several strains of Zygomycetes cultivated on glycerol produced mycelia rich in lipids containing higher amounts of neutral lipids (NL) than glycolipids plus sphingolipids and phospholipids (P), while biosynthesis of P in Mortierella ramanniana, Mucor sp., and Cunninghamella echinulata occurred though NL accumulation process was in progress. Polyunsaturated fatty acids (PUFA) concentration gradually decreased in all lipid fractions of M. ramanniana during growth. In contrast, in C. echinulata concentration of both linoleic and γ-linolenic acids increased with time, especially in P. Taking for granted that the main function of PUFA is associated to their participation in mycelial membranes, we could suppose that biosynthesis of these fatty acids is associated to mycelial growth. However, this is accurate only for some Zygomycetes, e.g., M. ramanniana. On the contrary, PUFA biosynthesis in C. echinulata persists after growth cessation, suggesting that in this species biosynthetic ability is not a strictly growth-associated process. Phosphatidyl-inositol and phosphatidyl-choline were the major P classes in C. echinulata and M. ramanniana, respectively. In M. ramanniana, a decrease of PUFA concentration was noticed even when mycelia were incubated in low temperature (conditions that normally favor PUFA biosynthesis), indicating that PUFA biosynthesis in this fungus is associated to primary metabolism.

Biodegradation of Crude Oil from the BP Oil Spill in the Marsh Sediments of Southeast Louisiana, USA

Abstract: The significant challenges presented by the April 20, 2010 explosion, sinking, and subsequent oil spill of the Deepwater Horizon drilling platform in Canyon Block 252 about 52 miles southeast of Venice, LA, USA greatly impacted Louisiana’s coastal ecosystem including the sea food industry, recreational fishing, and tourism. The short-term and long-term impact of this oil spill are significant, and the Deepwater Horizon spill is potentially both an economic and an ecological disaster. Microbes present in the water column and sediments have the potential to degrade the oil. Oil degradation could be enhanced by biostimulation method. The conventional approach to bioremediation of petroleum hydrocarbon is based on aerobic processes. Anaerobic bioremediation has been tested only in a very few cases and is still considered experimental. The currently practiced conventional in situ biorestoration of petroleum-contaminated soils and ground water relies on the supply of oxygen to the subsurface to enhance natural aerobic processes to remediate the contaminants. However, anaerobic microbial processes can be significant in oxygen-depleted subsurface environments and sediments that are contaminated with petroleum-based compounds such as oil-impacted marshes in Louisiana. The goal of this work was to identify the right conditions for the indigenous anaerobic bacteria present in the contaminated sites to enhance degradation of petroleum hydrocarbons. We evaluated the ability of microorganisms under a variety of electron acceptor conditions to degrade petroleum hydrocarbons. Researched microbial systems include sulfate-, nitrate-reducing bacteria, and fermenting bacteria. The results indicated that anaerobic bacteria are viable candidates for bioremediation. Enhanced biodegradation was attained under mixed electron acceptor conditions, where various electron-accepting anaerobes coexisted and aided in degrading complex petroleum hydrocarbon components of marsh sediments in the coastal Louisiana. Significant degradation of oil also occurred under sulfate-reducing and nitrate-reducing conditions.

Optimization of Elicitation Conditions with Methyl Jasmonate and Salicylic Acid to Improve the Productivity of Withanolides in the Adventitious Root Culture of Withania somnifera (L.) Dunal

Abstract: Adventitious root cultures derived from leaf derived callus of Withania somnifera (L.) Dunal were treated with methyl jasmonate and salicylic acid independently. Biomass accumulation, culture age, elicitation period, and culture duration were optimized for higher withanolides production in the two best-responding varieties collected from Kolli hills (Eastern Ghats) and Cumbum (Western Ghats) of Tamil Nadu, India. Between the two elicitors, salicylic acid (SA) improved the production of major withanolides (withanolide A, withanolide B, withaferin A, and withanone) as well as minor constituents (12-deoxy withastramonolide, withanoside V, and withanoside IV) in the Kolli hills variety. Treatment of root biomass (11.70 g FW) on 30-day-old adventitious root cultures with 150 μM SA for 4 h elicitor exposure period resulted in the production of 64.65 mg g−l dry weight (DW) withanolide A (48-fold), 33.74 mg g−l DW withanolide B (29-fold), 17.47 mg g−l DW withaferin A (20-fold), 42.88 mg g−l DW withanone (37-fold), 5.34 mg g−l DW 12-deoxy withastramonolide (nine fold), 7.23 mg g−l DW withanoside V (seven fold), and 9.45 mg g−l DW withanoside IV (nine fold) after 10 days of elicitation (40th day of culture) when compared to untreated cultures. This is the first report on the use of elicitation strategy on the significant improvement in withanolides production in the adventitious root cultures of W. somnifera.

Biohydrogen production from cheese whey wastewater in a two-step anaerobic process.

Abstract: Cheese whey-based biohydrogen production was seen in batch experiments via dark fermentation by free and immobilized Enterobacter aerogenes MTCC 2822 followed by photofermentation of VFAs (mainly acetic and butyric acid) in the spent medium by Rhodopseudomonas BHU 01 strain. E. aerogenes free cells grown on cheese whey diluted to 10 g lactose/L, had maximum lactose consumption (∼79%), high production of acetic acid (1,900 mg/L), butyric acid (537.2 mg/L) and H2 yield (2.04 mol/mol lactose; rate,1.09 mmol/L/h). The immobilized cells improved lactose consumption (84%), production of acetic acid (2,100 mg/L), butyric acid (718 mg/L) and also H2 yield (3.50 mol/mol lactose; rate, 1.91 mmol/L/h). E. aerogenes spent medium (10 g lactose/L) when subjected to photofermentation by free Rhodopseudomonas BHU 01 cells, the H2 yield reached 1.63 mol/mol acetic acid (rate, 0.49 mmol/L/h). By contrast, immobilized Rhodopseudomonas cells improved H2 yield to 2.69 mol/mol acetic acid (rate, 1.87 mmol/L/h). The cumulative H2 yield for free and immobilized bacterial cells was 3.40 and 5.88 mol/mol lactose, respectively. Bacterial cells entrapped in alginate, had a sluggish start of H2 production but outperformed the free cells subsequently. Also, the concomitant COD reduction for free cells (29.5%) could be raised to 36.08% by immobilized cells. The data suggest that two-step fermentative H2 production from cheese whey involving immobilized bacterial cells, offers greater substrate to- hydrogen conversion efficiency, and the effective removal of organic load from the wastewater in the long-term.

Expression of rice thaumatin-like protein gene in transgenic banana plants enhances resistance to fusarium wilt.

Abstract: The possibility of controlling Fusarium wilt—caused by Fusarium oxysporum sp. cubensec (race 4)—was investigated by genetic engineering of banana plants for constitutive expression of rice thaumatin-like protein (tlp) gene. Transgene was introduced to cauliflower-like bodies’ cluster, induced from meristemic parts of male inflorescences, using particle bombardment with plasmid carrying a rice tlp gene driving by the CaMV 35S promoter. Hygromycin B was used as the selection reagent. The presence and integration of rice tlp gene in genomic DNA confirmed by PCR and Southern blot analyses. RT-PCR revealed the expression of transgene in leaf and root tissues in transformants. Bioassay of transgenic banana plants challenged with Fusarium wilt pathogen showed that expression of TLP enhanced resistance to F. oxysporum sp. cubensec (race 4) compared to control plants.

Probiotics—Interactions with Bile Acids and Impact on Cholesterol Metabolism

Abstract: The use of probiotics, alone or in interaction with bile acids, is a modern strategy in the prevention and treatment of hypercholesterolemia. Numerous mechanisms for hypocholesterolemic effect of probiotics have been hypothesized, based mostly on in vitro evidence. Interaction with bile acids through reaction of deconjugation catalyzed by bile salt hydrolase enzymes (BSH) is considered as the main mechanism of cholesterol-lowering effects of probiotic bacteria, but it has been reported that microbial BSH activity could be potentially detrimental to the human host. There are several approaches for prevention of possible side effects associated with BSH activity, which at the same time increase the viability of probiotics in the intestines and also in food matrices. The aim of our study was to summarize present knowledge of probiotics—bile acids interactions, with special reference to cholesterol-lowering mechanisms of probiotics, and to report novel biotechnological approaches for increasing the pharmacological benefits of probiotics.

Mass Cultivation of Microalgae on Animal Wastewater: a Sequential Two-Stage Cultivation Process for Energy Crop and Omega-3-Rich Animal Feed Production

Abstract: In this study, 97 microalgal strains purchased from algae bank and 50 microalgal strains isolated from local waters in Minnesota were screened for their adaptability growing on a 20-fold diluted digested swine manure wastewater (DSMW). A pool of candidate strains well adapted to the DSMW was established through a high-throughput screening process. Two top-performing facultative heterotrophic strains with high growth rate (0.536 day−1 for UMN 271 and 0.433 day−1 for UMN 231) and one strain with high omega-3 unsaturated fatty acid (EPA, 3.75 % of total fatty acids for UMN 231) were selected. Subsequently, a sequential two-stage mixo-photoautotrophic culture strategy was developed for biofuel and animal feed production as well as simultaneous swine wastewater treatment using above two strains. The maximal biomass concentration and lipid content at the first and second stages reached 2.03 g/L and 23.0 %, and 0.83 g/L and 19.0 % for UMN 271 and UMN 231, respectively. The maximal nutrient removals for total phosphorus and ammonia after second-stage cultivation were 100 and 89.46 %, respectively. The experiments showed that this sequential two-stage cultivation process has great potential for economically viable and environmentally friendly production of both renewable biofuel and high-value animal feed and at the same time for animal wastewater treatment.

Sox9 Is Upstream of MicroRNA-140 in Cartilage

Abstract: MicroRNA-140 (miR-140) is specifically expressed in developing cartilage tissues. We have previously reported that miR-140 plays an important role during palatal cartilage development by modulating platelet-derived growth factor receptor alpha (pdgfra) in zebrafish. However, the regulatory mechanism of miR-140 in cartilage is still unknown. Using developing zebrafish, sox9a mutant (sox9a-/-) and sox9b mutant (sox9b-/-) zebrafish and SOX9 small interfering RNA in human chondrocytes, T/C-28 cells, we found that miR-140 is regulated by the cartilage master transcription regulator Sox9 in zebrafish and mammalian cells.

New tools for exploring "old friends-microbial lipases".

Abstract: Fat-splitting enzymes (lipases), due to their natural, industrial, and medical relevance, attract enough attention as fats do in our lives. Starting from the paper that we write, cheese and oil that we consume, detergent that we use to remove oil stains, biodiesel that we use as transportation fuel, to the enantiopure drugs that we use in therapeutics, all these applications are facilitated directly or indirectly by lipases. Due to their uniqueness, versatility, and dexterity, decades of research work have been carried out on microbial lipases. The hunt for novel lipases and strategies to improve them continues unabated as evidenced by new families of microbial lipases that are still being discovered mostly by metagenomic approaches. A separate database for true lipases termed LIPABASE has been created recently which provides taxonomic, structural, biochemical information about true lipases from various species. The present review attempts to summarize new approaches that are employed in various aspects of microbial lipase research, viz., screening, isolation, production, purification, improvement by protein engineering, and surface display. Finally, novel applications facilitated by microbial lipases are also presented.

Influence of Exogenous CO 2 on Biomass and Lipid Accumulation of Microalgae Auxenochlorella protothecoides Cultivated in Concentrated Municipal Wastewater

Abstract: The effects of exogenous CO2 on the growth and lipid accumulation of a local screened facultative heterotrophic microalgae strain Auxenochlorella protothecoides (UMN280) as well as nutrient removal from concentrated municipal wastewater stream (centrate) were examined in this study. A 12-day batch experiment was conducted with CO2 aeration at three levels, namely, 0%, 1%, and 5% (v/v) CO2 mixed with air, under light intensity of 60 μmol/(m2 @@s). A two-stage growth pattern was observed. The first stage (first–fifth day) was dominated by heterotrophic growth in which organic carbon was the main carbon source. The second stage (6th–12th day) was dominated by autotrophic growth in which exogenous CO2 had a positive effect on algal biomass accumulation. The addition of 5% CO2 was better than that of 1% CO2 on the biomass and lipid production. The uptakes of nutrients were similar between injection and no injection of CO2, except on phosphorus removal which was affected by the acidification of CO2.

Lactobacillus plantarum AS1 isolated from south Indian fermented food Kallappam suppress 1,2-dimethyl hydrazine (DMH)-induced colorectal cancer in male Wistar rats.

Abstract: The relationship between antioxidant and anticancer properties of probiotic bacterium strain Lactobacillus plantarum AS1 (AS1) in colon cancer induced by 1,2-dimethylhydrazine (DMH) has been studied. In this study, an increased level of lipid peroxide (LPO) products and increased activities of antioxidant enzymes (superoxide dismutase, catalase and glutathione-S transferase) and marker enzymes (alkaline phosphatase and acid phosphatase) in colon and plasma of cancer-bearing animals have been observed. AS1 was supplemented either before initiation or during initiation and selection/promotion phases of colon carcinogenesis and was found to be effective in altering lipid peroxidation and antioxidant enzyme activities and marker enzymes to a statistically significant level measured either in the colon and in the plasma. These alterations inclined towards normal in a time-dependent manner on AS1 supplementation. The mean tumor volume diameter and total number of tumors were found to be statistically decreased in AS1 pre- and post-treated rats. Furthermore, histopathological examination shows remarkable difference between control and treated groups. The in vitro antioxidant assay shows that AS1 has promising antioxidant property. These results demonstrate that AS1 strain can modulate the development of DMH-induced rat colon carcinogenesis through an antioxidant-dependent mechanism.

Nano-TiO2-Induced Apoptosis by Oxidative Stress-Mediated DNA Damage and Activation of p53 in Human Embryonic Kidney Cells

Abstract: The aim of the present study is to explore the mechanism of cytotoxic and genotoxic effects of TiO2 nanoparticles on human embryonic kidney (HEK-293) cells. Toxicity was evaluated using changes in various cellular parameters of HEK-293 cells like morphology, viability, metabolic activity, oxidative stress and apoptosis. Oxidative stress was measured by the level of reactive oxygen species (ROS), lipid peroxidation, superoxide dismutase, catalase and glutathione peroxidase. Apoptosis induced by nano-TiO2 was characterized by PI staining and DNA ladder assay. Furthermore, apoptotic proteins such as p53 and Bax were analysed by western blot. Our results indicate that nano-TiO2 induces cytotoxicity in a time- and dose-dependent manner. Oxidative stress and apoptosis were induced by exposure to nano-TiO2. Moreover, the expression of p53, Bax and caspase-3 were increased in a dose-dependent pattern. In conclusion, ROS-mediated oxidative stress, the activation of p53, Bax, caspase-3 and oxidative DNA damage are involved in the mechanistic pathways of nano-TiO2-induced apoptosis in HEK-293 cells.

Degradation of Polyurethane by Aspergillus flavus (ITCC 6051) Isolated from Soil

Abstract: The present study deals with the isolation of fungi from soil with the ability to degrade polyurethane (PU). A pure fungal isolate was analyzed for its ability to utilize PU as a sole carbon source in shaking culture for 30 days. Incubation of PU with Aspergillus flavus resulted in 60.6% reduction in weight of PU. The scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR) results showed certain changes on the surface of PU film and formation of some new intermediate products after polymer breakdown. Thermogravimetric curves showed changes between the thermal behavior of the samples that were inoculated with A. flavus and control. FTIR spectra showed detectable changes in control and incubated samples, suggesting that degradation occurs, with the decreased intensity of band at 1,715 cm(-1), corresponding to ester linkages. We have identified an extracellular esterase activity which might be responsible for the polyurethanolytic activity.

Effect of Substrate Concentration on Dark Fermentation Hydrogen Production Using an Anaerobic Fluidized Bed Reactor

Abstract: The effect of substrate (glucose) concentration on the stability and yield of a continuous fermentative process that produces hydrogen was studied. Four anaerobic fluidized bed reactors (AFBRs) were operated with a hydraulic retention time (HRT) from 1 to 8 h and an influent glucose concentration from 2 to 25 g L−1. The reactors were inoculated with thermally pre-treated anaerobic sludge and operated at a temperature of 30 °C with an influent pH around 5.5 and an effluent pH of about 3.5. The AFBRs with a HRT of 2 h and a feed strength of 2, 4, and 10 g L−1 showed satisfactory H2 production performance, but the reactor fed with 25 g L−1 of glucose did not. The highest hydrogen yield value was obtained in the reactor with a glucose concentration of 2 g L−1 when it was operated at a HRT of 2 h. The maximum hydrogen production rate value was achieved in the reactor with a HRT of 1 h and a feed strength of 10 g L−1. The AFBRs operated with glucose concentrations of 2 and 4 g L−1 produced greater amounts of acetic and butyric acids, while AFBRs with higher glucose concentrations produced a greater amount of solvents.

Synthesis, characterization, and oil recovery application of biosurfactant produced by indigenous pseudomonas aeruginosa WJ-1 using waste vegetable oils.

Abstract: A bacterial strain was isolated and cultured from the oil excavation areas in tropical zone in northern China. The biochemical characteristics and partial sequenced 16S rRNA gene of isolate, WJ-1, was identical to those of cultured representatives of the species Pseudomonas aeruginosa. This bacterium was able to produce a type of biosurfactant. Compositional analysis revealed that the extracted biosurfactant was composed of high percentage lipid (∼74%, w/w) and carbohydrate (∼20%, w/w) in addition to a minor fraction of protein (∼6%, w/w). The best production of 50.2 g/l was obtained when the cells were grown on minimal salt medium containing 6.0% (w/v) glucose and 0.75% (w/v) sodium nitrate supplemented with 0.1% (v/v) element solution at 37 °C and 180 rpm after 96 h. The optimum biosurfactant production pH value was found to be 6.0–8.0. The biosurfactant of WJ-1, with the critical micelle concentration of 0.014 g/L, could reduce surface tension to 24.5 mN/m and emulsified kerosene up to EI24 ≈95. The results obtained from time course study indicated that the surface tension reduction and emulsification potential was increased in the same way to cell growth. However, maximum biosurfactant production occurred and established in the stationary growth phase (after 90 h). Thin layer chromatography, Fourier transform infrared spectrum, and mass spectrum analysis indicate the extracted biosurfactant was affiliated with rhamnolipid. The core holder flooding experiments demonstrated that the oil recovery efficiency of strain and its biosurfactant was 23.02% residual oil.

Antioxidant, anti-inflammatory, and anti-senescence activities of a phlorotannin-rich natural extract from brown seaweed Ascophyllum nodosum

Abstract: Aging at the cellular level is characterized by oxidative stress, inflammation, and cell senescence. An extract of the brown seaweed Ascophyllum nodosum rich in phlorotannins has been studied for its inhibitory activity against oxidative stress, inflammation, and senescence. A. nodosum extract at 0.2 % prevented tBHP-induced reactive oxygen species production (evaluated using the H2DCF-DA test in cytofluorometry) in epithelial cells and LPS-induced TNF-α and IL-6 release (evaluated using ELISA technique) in macrophages. A. nodosum extract also increased nuclear SIRT1 activity in epithelial cells. Altogether, these beneficial cellular effects of phlorotannin-rich A. nodosum extract could be used in topical therapeutic formulations against aging.

Recent Advances on Filamentous Fungal Biofilms for Industrial Uses

Abstract: Industrial enzymes are produced by submerged fermentation (SF) and by solid-state fermentation (SSF) to a lesser extent. Although SSF has several advantages, its scale-up is difficult. The role of physiological and genetic properties of microorganisms growing attached to surfaces could explain the advantages of SSF. Filamentous fungi are naturally adapted to growth on surfaces and in these conditions they show a particular physiological behavior which is different from that in SF; thus, they also form biofilms. Fermentation by filamentous fungal biofilms (FFB) is a homogeneous production system within a liquid environment based on the infrastructure of the SF process with the productive efficiency of the SSF. Enzyme production levels of FFB are much higher than those obtained in SF and they are also amenable of mixed fungal cultivation. Transcriptomic and proteomic tools are used to uncover the fundamental biological issues behind FFB. Several genes encoding cellulolytic enzymes are either differentially expressed or overexpressed in FFB. Moreover, our proteomic studies of Aspergillus niger biofilms compared to SF indicate that many intracellular proteins are either differentially expressed or overexpressed. Clinically important fungi like A. fumigatus also form biofilms when they infect lungs and recent studies demonstrate same gene expression features. These results support our hypothesis of cell adhesion and its role in the new schemes for improved fermentative production of industrial enzymes.