Search

Urbanization is a revolutionary and necessary step for the development of nations. However, with development emanates its drawback i.e., generation of a huge amount of wastewater. The existence of diverse types of nutrient loads and toxic compounds in wastewater can reduce the pristine nature of the ecosystem and adversely affects human and animal health. The conventional treatment system reduces most of the chemical contaminants but their removal efficiency is low. Thus, microalgae-based biological wastewater treatment is a sustainable approach for the removal of nutrient loads from wastewater. Among various microalgae, Tetraselmis sp. is a robust strain that can remediate industrial, municipal, and animal-based wastewater and reduce significant amounts of nutrient loads and heavy metals. The produced biomass contains lipids, carbohydrates, and pigments. Among them, carbohydrates and lipids can be used as feedstock for the production of bioenergy products. Moreover, the usage of a photobioreactor (PBR) system improves biomass production and nutrient removal efficiency. Thus, the present review comprehensively discusses the latest studies on Tetraselmis sp. based wastewater treatment processes, focusing on the use of different bioreactor systems to improve pollutant removal efficiency. Moreover, the applications of Tetraselmis sp. biomass, advancement and research gap such as immobilized and co-cultivation have also been discussed. Furthermore, an insight into the harvesting of Tetraselmis biomass, effects of physiological, and nutritional parameters for their growth has also been provided. Thus, the present review will broaden the outlook and help to develop a sustainable and feasible approach for the restoration of the environment.

Realising the hazardous effect of nickel on human health, microbes and plants are effectively used for bioremediation. The endophytic microorganisms have an important role in the phytoremediation of nickel using Vigna radiata. Therefore, in order to harness the potential of microbial strains, the present study was designed to examine the metal biosorption ability of endophytic bacterial strains isolated from plants growing in nickel-contaminated soil. A total of six endophytic nickel resistance bacteria were isolated from the plant Vigna radiata. The metal tolerant bacterial strains were identified following 16 S rRNA gene sequence analysis. Nickel biosorption estimation and plant growth-promoting (PGP) activities of isolated strains were performed and found high nickel biosorption efficiency of 91.3 ± 0.72% at 600 mg L−1 using Bacillus safensis an isolated endophytic strain from Vigna radiata. Furthermore, high indole acetic acid (IAA) and exopolysaccharide (EPS) production were obtained in all the strains as compared to without nickel-containing medium used as control. Moreover, the production of high EPS suggests improved biosorption ability of isolated endophytic strains. In addition, a kinetic study was also performed to evaluate different adsorptions isotherms and support the nickel biosorption ability of endophytic strains. The treatment of nickel electroplating industrial effluent was also demonstrated by isolated endophytic strains. Among six (6) strains, B. cereus showed maximum 57.2 ± 0.62% biosorption efficiency of nickel which resulted in the removal of 1003.50 ± 0.90 mg L−1 of nickel from the electroplating industry effluents containing initial 1791 ± 0.90 mg L−1 of nickel. All other strains were also capable of significant nickel biosorption from electroplating industry effluents as well. Thus, isolated endophytic nickel tolerant strains can be further used at large-scale biosorption of nickel from electroplating industry effluent.

The oxidation activity of multicopper-oxidases overlaps with different substrates of laccases and bilirubin oxidases, thus in the present study an integrated approach of bioinformatics using homolo...

Stenohaline freshwater fish with narrow salinity tolerance are susceptible to saline stress from global climate change and anthropogenic activities. The present study elucidated that saline exposure during the sensitive window of preparatory phase of oocyte maturation significantly affected gonadosomatic index, ovarian histology and morphometric features of oocytes in a stenohaline freshwater catfish, Heteropneustes fossilis (Bloch, 1794) in a dose (2 ppt, 5 ppt)—and duration (8, 24 days)‐dependent manner. The gonads of H. fossilis show annual maturation cycle. Loss of integrity of ovigerous lamellae, disruption of ovarian stroma, disrupted oolemma, ooplasmic vacuolization, damaged germinal vesicles and altered morphometry of previtellogenic oocytes, such as chromatin‐nucleolus, early perinucleolar and late perinucleolar, elucidated consistent effects of saline exposure except at 8 days exposure to 2 ppt of saline. Increased salinity might have affected the transmembrane ion/water transport and disrupted the osmotic balance in ovary that eventually led to impairment in growth of ovary and oocyte maturation. The susceptibility of ovary to comparatively less concentrations of saline exposure might be due to sensitiveness of ovary/oocytes during the early phase of growth. Fluctuating salinity along with other stressors can affect metabolic and growth rates, fecundity and ultimately survival of fish.

The wastewater originates from different industrial, municipal, and agriculture processes and contains different nitrogen sources, for example, nitrate, ammonium, nitrite, and phosphate such as inorganic and organic sources. The discharge of high nitrate and phosphate to the ecosystem or nearby water bodies can cause eutrophication which disbalances the aquatic ecosystem. Furthermore, ingestion of these pollutants can cause severe toxicity and disease to humans and animals. Thus, from an environmental and social perspective, its treatment is essential with no negative impact on the ecosystem. Microalgae are fundamental, mixotrophic microorganisms that treat different wastewater and utilize nitrate and phosphate in the medium as a source of nutrients. Among them, Picochlorum sp., have the potential to remove nitrogen and phosphate from wastewater. The biomass produced by Picochlorum sp. can be a promising candidate as a sustainable feedstock for biofuel and bioproducts formation. Thus, the present review provides a brief knowledge and understanding about the concentration of nitrogen and phosphate in different wastewater, their negative impacts, and the uptake mechanism of microalgae. Furthermore, the review also provides an insight into Picochlorum sp., and the effects of different physiological and nutritional factors on their growth, wastewater treatment efficacy, and biomass for value-added products and biorefinery applications. In addition, the review is useful to understand the potential of Picochlorum sp. for a tenable wastewater treatment process.

Xylooligosaccharides (XOS) from lignocellulosic biomass (LCB) have found widespread applications in food, feed, nutraceuticals and pharamecutical industries. Enzymatic degradation of LCB for generation of XOS have gained impetus in recent times In the present investigation an extracellular thermo-alkali stable xylanase from Aspergillus oryzae LC1 was purified by using PEG 8000/MgSO4 aqueous two-phase system and was capable of hydrolysing various agricultural residues into XOS system. Highest activity was observed using 11.3% (w/w) PEG 8000 and 22.5% (w/w) sulphate salt with maximum purification factor (13-fold), highest yield (86.8%) and partition coefficient (8.8%). The purification of the crude enzyme also resulted in decrement of β-xylosidase activity (29.8 U/mL to 0.6 U/mL). The molecular weight of enzyme was estimated ~35 kDa. The highest residual activity was obtained with birch wood xylan as substrate with Km and Vmax of 0.2 mg/mL and 172.2 μmol min−1 mg−1 respectively. The metal ions Fe2+, Ag2+, Mg2+, Mn+ and Co+ enhanced xylanase activity while EDTA, DMSO and SDS acted as inhibitor. The effect of Fe+2 was confirmed by the circular dichroism experiment. The partially purified enzyme was capable of generating XOS i.e. xylobiose (0.68 mg/g), xylotriose (2.47 mg/g) and xylotetraose (2.29 mg/g) by direct enzymatic hydrolysis of untreated sugarcane baggase, wheat straw and wheat bran respectively.

Microalgae biomass have been used as a source of nutrient-rich food, feed, and health-promoting compounds. Among the several commercially available microalgae, Haematococcus pluvialis is the most abundant source of natural astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione), which is considered as “super antioxidant.” Therefore natural astaxanthin produced by H. pluvialis has a higher antioxidant capacity than the synthetic sources, which reduces oxidative stress and free radicals and helps the human body to maintain a healthy state. However, H. pluvialis contains astaxanthin inside the cells, which need to be extracted using nontoxic extraction technologies for different application. Among the different available extraction technologies, supercritical fluid extraction (SFE) is a modern technology with increasing applications in pharmaceutical and nutraceutical sector. The most frequently employed supercritical solvent in food and natural product processing is carbon dioxide (CO2) due to its low critical temperature and pressure while considered as nontoxic extraction solvent. Therefore, nowadays, supercritical carbon dioxide (SC-CO2) is considered as a new substitute for complete extraction of natural compounds from different matrices. However, the extraction efficiency and purity of astaxanthin in the extract are influenced by different operative conditions such as the extraction pressure, temperature, time, and use of cosolvent. Hence the optimum operative condition of SC-CO2 extraction could enhance the extraction yields of astaxanthin and of its purity the extract. Therefore present chapter summarizes the effects of several extraction parameters on SC-CO2 extraction of astaxanthin from H. pluvialis, which could serve as benchmark for future development of SC-CO2 extraction technology and its commercial implementation in pharmaceutical and nutraceutical sector.

In the present study, specificity of laccase from Stropharia sp. ITCC-8422 against various substrates, i.e. 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,6-dimethoxyphenol (DMP), guaiacol (GCL) and syringaldazine (SYZ) was determined. It exhibited maximum affinity against ABTS, followed by DMP and negligible activity for GCL and SYZ. As the concentration of substrate increased from 0.5 to 1.5 mM (ABTS) and 1 to 5 mM (DMP), the activity increased from 301.1 to 567.8 U/L and 254.4 to 436.2 U/L. Further, quadrupole time-of-flight liquid chromatography mass spectrometry (QTOF-LCMS) analysis of the extracellular proteome of Stropharia sp. ITCC-8422 identified eighty-four (84) extracellular proteins. The peptide sequence for the enzyme of interest exhibited sequence similarity with laccase-5 of Trametes pubescens. Using high molecular mass sequence of laccase-5, the protein structure of laccase was modelled and binding energy of laccase with four substrates, i.e. ABTS (− 5.65), DMP (− 4.65), GCL (− 4.66) and SYZ (− 5.5) was determined using autodock tool. The experimental and in silico analyses revealed maximum activity of laccase and lowest binding energy with ABTS. Besides, laccase was purified and it exhibited 2.1-fold purification with purification yield of 20.4% and had stability of 70% at pH 5–9 and 30–40 ℃. In addition, the bioremediation potential of laccase was explored by in silico analysis, where the binding energy of laccase with alizarin cyanine green was − 6.37 and both in silico work and experimental work were in agreement. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-020-02399-8) contains supplementary material, which is available to authorized users.

Laccase has the ability to act on a broad range of substrates, as a result of which multiple compounds have been used for laccase assay and numerous applications have been discovered over time. Thus, considering the above points, in the present study, white and blue laccase from Myrothecium verrucaria ITCC-8447 and Pleurotus ostreatus were used for laccase assay using various substrates which includes 2,2′ azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,6-dimethoxyphenol (2, 6 DMP), guaiacol (GCL), and syringaldazine (SYZ). The most effective substrate of the four substrates was ABTS for white and blue laccase. The white and blue laccase were further used for the synthesis of bio-material via fungal-assisted treatment of wheat bran (WB) and sugarcane bagasse (SB) followed by micro-wave pre-treatment and the addition of starch and glycerol to the treated agro-residue in the ratio of 5:1:1. The thickness swelling and water absorption percentage was minimum for wheat bran synthesized bio-material using white laccase in comparison to the other synthesized bio-material.

Xylanase is a well-known enzyme for the conversion of agricultural biomass into xylose using enzymatic hydrolysis process. Agricultural residues are the rich source of lignocellulosic biomass. Recently there has been increasing interest in the use of agricultural residues for the production of industrially important enzymes along with other value-added by-products. Large-scale purification of the desired enzyme from fermentation broth and purification of enzymes via economically feasible methods are the main obstacle in biotechnological industries. In the present study, aqueous two-phase system (ATPS) was utilized for the purification of extracellular crude xylanase obtained from the submerged culture of Aspergillus oryzae LC1 (ITCC-8571/NAIMCC-F-03390). Various sulphate salts were tested for xylanase purification, among them MgSO4 showed best results with PEG and was selected for further studies. Response surface methodology based on Box-Behnken design was used for optimizing the ATPS parameters, such as the molecular weight of PEG, MgSO4 and PEG concentration. The purification factor of xylanase was found maximum in the presence of high-molecular-weight PEG (8000), PEG intermediate concentration (11.3% w/w) and high MgSO4 salt concentration (22.5% w/w). A 13-fold increase in purification factor was obtained under optimized conditions, with partition coefficient 8.8% and enzyme yield 86.8% at the top phase. The partially purified xylanase obtained using ATPS was further used for the enzymatic hydrolysis of different agricultural residues, followed by the analysis of the hydrolysis products by TLC.

Advanced techniques of enzyme production and purification have become prerequisite due to their diverse industrial applications. There is an utmost requirement for screening of new strains capable of synthesising industrially useful enzymes. The present study reports the production and profiling of extracellular proteins expressed by the newly isolated strain of a filamentous fungus, Aspergillus oryzae LC1. The extracellular enzyme production was done by submerged fermentation using Mendel’s and Sternberg’s medium (MSM), and its optimisation was done using one factor at a time (OFAT). The presence of xylanase was confirmed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and zymography. In addition, the profiling of extracellular proteome of Aspergillus oryzae LC1 was carried out by liquid chromatography coupled tandem mass spectrometry (LC-MS/MS). In this study, media optimisation showed 5.7-fold increase in xylanase activity. The multiple bands observed in zymography revealed the presence of various forms of xylanase. A total of 73 proteins were identified in LC-MS/MS analysis. Functional classification showed that the hydrolytic enzymes consisted of 48% glycoside hydrolase, 11% proteases, 1% polysaccharide lyase and esterase’s, 9% oxidoreductases and 30% other proteins. A total of 26 families of glycosidic hydrolase were detected with other protein families such as serine peptidase, S, LysM, G-D-S-L, M35, carboxyl esterase (CE1), pectate lyase (PL) and oxidoreductases. Among the huge diversity of synergistically acting biomass cleaving enzymes, endo-1, 4-β xylanase with isoforms: xyn F1, xyn B, β xylanase and xyn 11A belonging to GH10 family covered the major portion of the total percentage of identified proteins. As per our knowledge, this is the first report of extracellular proteome analysis of Aspergillus oryzae LC1 suggesting its capability for recombinant expression and evaluation in hemicellulose deconstruction applications.

In the present investigation, cloning and overexpression of xylanase (XynF1), the main xylanase of A. oryzae LC1, was performed in prokaryotic system E. coli BL21(DE3) to produce recombinant xylanase with high titer of specific activity (1037.3 U/mg), which was 9.3-fold higher than the native strain. Further, the recombinant XynF1 of size 37 kDa was purified using Ni2+-NTA resins followed by cation exchange chromatography, which showed an 1.8-fold increase in purity with 71.4% yield. The r-XynF1 exhibited a wide range of activity at different pH (3.0–10.0) range and temperature (30–70 °C) with an optimum pH at 5.0 and temperature at 30 °C. The results from the current study, clearly demonstrate that this is an effective method to generate a recombinant enzyme with improved activity, making it useful for possible industrial applications.

Myco-valorization (Myco-Valtn) concept was explored using Myrothecium verrucaria ITCC-8447 via column bioreactor to remove two anthraquinone (ARq) dyes. Among the three myco-valtn approaches free cell dependent enabled more than 80% removal of Anthraquinone violet R (AVR) and Alizarin cyanine green (ACG) after 48 h at 30 ± 2 °C. Enzymatic treatment removed more than 50% AVR and ACG after 10 min. However, synthetic and natural support entrapment on Scotch-Brite® (SB) and Luffa cylindrica (LC) enabled more than 80% removal in SB-ACG and LC-ACG and more than 60% in SB-AVR and LC-AVR in 6th cycle. The regenerated column enhanced the removal of dye and allowed the column to run for multiple cycles. Further after FTIR XRD and LCMS Q-TOF, analysis it was observed that ACG and AVR were completely degraded and laccase played the key roles in the degradation of ACG and AVR and the degraded metabolites of anthraquinone dyes (ACG and AVR) exhibited much less toxicity than the parent dye using phytotoxicity assays.

In the present work attempts have been made to mimic the natural system of biomass delignification using laccase from Myrothecium verrucaria ITCC-8447 and synergistic effect of cellulase and xylanase from Schizophyllum commune NAIMCC-F-03379 and Aspergillus oryzae ITCC-8571 respectively for enhanced saccharification and subsequent bioethanol production. The laccase mediated pretreatment resulted in 6.7% delignification of rice straw (RS). The structural analysis of enzymatic pretreated RS using XRD and FTIR suggested high crystallinity index (CrI) and improved accessibility of cellulose and hemicelluloses as compared to untreated RS. The single step simultaneous delignification, saccharification and fermentation (SDSF) of RS using partially purified in-house enzyme cocktail with Saccharomyces cerevisiae MTCC-173 resulted in sugar yield of 26.7 ± 0.2 g/L with an experimental ethanol yield of 6.47 ± 0.16 g/L which is comparable to maximum sugar and ethanol yield of 31.2 ± 0.7 g/L and 7.34 ± 0.39 g/L respectively using commercial enzyme cocktail with S. cerevisiae MTCC-173. The SDSF was obtained as a suitable single step process for the ethanol production from RS.

Multicopper oxidases (MCOs) has a unique feature of having the presence of four Cu atoms arranged into three (Type I, II and III) spectral classification. MCOs laccase due to its broad range of substrate specificity has numerous biotechnological applications. The two types of laccases include the typical blue and the atypical white, yellow laccases which have been isolated from diverse geographical locations globally. In the present study laccases were identified using Liquid Chromatograph Mass Spectrometer Studies (LCMS) study where blue laccase exhibited homology with Trametes villosa Q99044 and Q99046 and white, yellow laccase exhibited homology with Myrothecium verrucaria OX = 1859699; Q12737 and Trametes versicolor Q12717 respectively. The spectral comparison between laccases were determined via spectroscopic analysis where UV-spectra of blue laccase from Trametes versicolor had a peak at 605 nm (Type I Cu atom) whereas in case of white and yellow laccases the peak was absent and in addition had an absorption peak at 400nm. It was followed by X-Ray Diffraction (XRD) analysis of proteins where α-helix (10°) and β-sheet (22°) structure were observed in case of all the three laccases. However, the intensity of α-helix in white and yellow laccase was stronger as compared to the blue laccase whereas the intensity of β-sheet was stronger in case of blue laccase as compared to other two laccases. Further, Fourier-transform infrared spectroscopy (FTIR) analysis was performed which enabled the analysis of proteins where α-helix (1650–1658 cm−1), β-sheets (1620–1640 cm−1), amide I (1700−1600 cm−1) amide II (bands at under 1400 cm−1) and amide A, B (bands above 3000 cm−1)., Bioinformatics; Microbiology; Structural biology; Mycology; Microorganism; Enzymology; Proteomics; Spectroscopy; Laccase; LCMS; UV-Spectra; XRD; FTIR

The white laccase was produced from Myrothecium verrucaria ITCC-8447 under submerged fermentation. The media components were optimized by response surface methodology (CCD-RSM). The nutritional components (glucose and peptone) and physical parameters (pH and temperature) were optimized by response surface methodology for enhanced laccase production by Myrothecium verrucaria ITCC-8447. The enzyme activity under optimum condition exhibited 1.45 fold increases in laccase activity. The white laccase was subjected to ion exchange chromatography with 6 fold purification. The molecular weight of white laccase was ~63-75kDa as estimated by SDS-PAGE followed by the activity staining with ABTS where green bands confirmed the presence of laccase. The enzyme was stable over an alkaline pH range of 7-9 and the temperature range of 30-40°C. The characterization of white laccase was done by CD spectra, UV-visible absorption, FTIR and XRD. The Km and Vmax values of the purified laccase were 2.5mM and1818.2μmol/min/L. The delignification capability of the white laccase was determined by reduction in Kappa number (58.8%) and Klason lignin (64.7%) of wheat straw after 12h of incubation. Further the delignification was confirmed FTIR and XRD.

In this study, keratinolytic potential of a Sodium Dodecyl Sulfate (SDS) degrading strain of Pseudomonas stutzeri strain K4 was evaluated. Strain K4 completely metabolized 1% (w/v) chicken feathers after 72 h of incubation with production of 784.2 µg/ml of soluble protein and 42 U/ml of keratinase. Scanning Electron Microscopy (SEM) analysis of chicken feathers indicated damage on the surface of feathers. Activity staining for keratinase showed presence of five keratinases (26–76 kDa) during growth with chicken feathers. Optimum pH and temperature for crude keratinase was found to be pH-8 and 40 °C respectively. Crude keratinase showed activation in presence of metal ions such as Mg2+ (39%), Mn2+ (28%), Na+ (20.8%), solvents such as isopropanol (30.7%), glycerol (28.2%), reducing agents such as β- mercaptoethanol (70%), chelating agents such as EDTA (25.3%) and anionic detergent SDS (37.8%), respectively. Crude keratinases showed high substrate specificity for keratin and chicken feathers, low specificity for collagen and hair, respectively. Dehairing of goat skin by employing crude ketainase preparation (40 U/ml) indicated complete dehairing after 20 h of incubation. Enzymatic dehairing was superior over chemical dehairing, as no damage to skin and hairs were observed. This is the first report of a novel strain of P. stutzeri exhibiting excellent dehairing activity; results indicate that purification of keratinases prior to dehairing was not required.

Cyanobacteria have tremendous applications in areas such as production of biofuels and pharmaceutically important pigments and are used as an adsorbent for the removal of toxic metabolites. However, large scale production of Cyanobacteria is not economically feasible due to high cost involved in separation of biomass. In this context, different attachment systems have been developed for the growth of Cyanobacteria on a solid support. In this study, a simple and economical attachment system using polystyrene foam for growth of Cyanobacteria has been presented. Results clearly indicate that high biomass yield can be obtained in attached system when compared to suspended system. In attachment system, the biomass yield showed 21.4%, total protein content showed 29.2%, chlorophyll content showed 11.1%, and carotenoid content showed 13.1% increase as compared to the suspended system. The attachment system can also support the growth of Cyanobacteria in presence of copper mine waste water with concomitant removal of copper ions. These results were corroborated by COD analysis, which indicated significant reduction. Further, copper removal was high in attached system as compared to suspended system. It appears that attachment system offers protection for growing Cyanobacteria and can be effectively employed for growing Cyanobacteria in presence of waste water coming from different sources.

Malachite green (MG) is a highly toxic, and recalcitrant tri-phenyl methane dye, which can be adsorbed on surface of chicken feathers, a non toxic poultry waste. This interaction can affect metabolism of chicken feathers by microbes in the environment. In this study, decolorization/degradation of MG and metabolism of MG adsorbed chicken feathers by Pseudomonas mendocina strain PM2 has been evaluated. Decolorization of different concentrations of MG by strain PM2 was studied. Degradation of MG was studied by UV–vis/FTIR analysis. Enzyme activities of selected enzymes were evaluated in order to ascertain their role in MG degradation. Microbial/phytotoxocity studies on MG and its degraded metabolites were carried out to confirm detoxification of MG after degradation. MG was adsorbed on surface of chicken feathers and its toxicity on strain PM2 and MG sensitive strain of Bacillus subtilis MTCC 441 was evaluated. Metabolism of native and MG adsorbed chicken feathers by strain PM2 and MTCC 441 was studied. Results showed that strain PM2 could decolorize up to 1800 mg/L MG. UV–vis/FTIR studies indicated degradation of MG by strain PM2. Assay of enzyme activity indicated involvement of MG reductase, lignin peroxidase and manganese peroxidase during degradation. Microbial/phytotoxicity study confirmed biodetoxification of MG after degradation. MG adsorbed chicken feathers were toxic to MTCC 441 and non toxic to strain PM2. Further, strain PM2 was able to metabolize MG adsorbed chicken feathers whereas MTCC 441 could not metabolize MG adsorbed chicken feathers. This study clearly indicates that MG adsorbed chicken feathers are difficult to be metabolized by MG sensitive strains.

Beech and pine wood blocks were treated with 1,3-dimethylol-4,5-dihydroxyethylen urea (DMDHEU) to increasing weight percent gains (WPG). The resistance of the treated specimens against Trametes versicolor and Coniophora puteana, determined as mass loss, increased with increasing WPG of DMDHEU. Metabolic activity of the fungi in the wood blocks was assessed as total esterase activity (TEA) based on the hydrolysis of fluorescein diacetate and as heat or energy production determined by isothermal micro-calorimetry. Both methods revealed that the fungal activity was related with the WPG and the mass loss caused by the fungi. Still, fungal activity was detected even in wood blocks of the highest WPG and showed that the treatment was not toxic to the fungi. Energy production showed a higher consistency with the mass loss after decay than TEA; higher mass loss was more stringently reflected by higher heat production rate. Heat production did not proceed linearly, possibly due to the inhibition of fungal activity by an excess of carbon dioxide. peerReviewed

Silver nanoparticles (SNPs) are used extensively in areas such as medicine, catalysis, electronics, environmental science, and biotechnology. Therefore, facile synthesis of SNPs from an eco-friendly, inexpensive source is a prerequisite. In the present study, fabrication of SNPs from the leaf extract of Butea monosperma (Flame of Forest) has been performed. SNPs were synthesized from 1% leaf extract solution and characterized by ultraviolet-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). The mechanism of SNP formation was studied by Fourier transform infrared (FTIR), and anti-algal properties of SNPs on selected toxic cyanobacteria were evaluated. TEM analysis indicated that size distribution of SNPs was under 5 to 30 nm. FTIR analysis indicated the role of amide I and II linkages present in protein in the reduction of silver ions. SNPs showed potent anti-algal properties on two cyanobacteria, namely, Anabaena spp. and Cylindrospermum spp. At a concentration of 800 μg/ml of SNPs, maximum anti-algal activity was observed in both cyanobacteria. This study clearly demonstrates that small-sized, stable SNPs can be synthesized from the leaf extract of B. monosperma. SNPs can be effectively employed for removal of toxic cyanobacteria.

A novel dye-decolourizing strain of the bacterium Serratia marcescens efficiently decolourized two chemically different dyes Ranocid Fast Blue (RFB) and Procion Brilliant Blue-H-GR (PBB-HGR) belonging respectively to the azo and anthraquinone groups. Extracellular laccase and manganese peroxidase (MnP) activity were detected during dye decolourization. The involvement of MnP activity was found in the decolourization of both dyes. More than 90% decolourization of PBB-HGR and RFB was obtained on days 8 and 5, respectively at 26 °C under static conditions at pH 7.0. MnP activity was increased by the addition of Mn2+ · At 50 μM Mn2+, high MnP (55.3 U/ml) but low laccase activity (8.3 U/ml) was observed. Influence of oxalic acid on MnP activity was also observed.

Neem hull waste (containing a high amount of lignin and other phenolic compounds) was used for lignin peroxidase production by Phanerochaete chrysosporum under solid-state fermentation conditions. Maximum decolorization achieved by partially purified lignin peroxidase was 80% for Porocion Brilliant Blue HGR, 83 for Ranocid Fast Blue, 70 for Acid Red 119 and 61 for Navidol Fast Black MSRL. The effects of different concentrations of veratryl alcohol, hydrogen peroxide, enzyme and dye on the efficiency of decolorization have been investigated. Maximum decolorization efficiency was observed at 0.2 and 0.4 mmol/L hydrogen peroxide, 2.5 mmol/L veratryl alcohol and pH 5.0 after a 1-h reaction, using 50 ppm of dyes and 9.96 mkat/L of enzyme.

Cellulose was treated with various concentrations of 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU) to obtain different DMDHEU contents in the cellulose preparation. The release of sugars due to hydrolysis by a cellulase enzyme complex clearly decreased with increasing DMDHEU content. When the cellulose preparation with the highest DMDHEU content was subjected to pretreatment with Fenton's reagent (Fe2+, H2O2), the sugar release increased 4.5-fold. Incubation of modified cellulose with only H2O2did not increase sugar release by cellulase. Compared to cellulose, the sugar release from milled wood powder induced by cellulase was very low but still decreased due to treatment with DMDHEU. Sole incubation of wood powder with Fenton's reagent did barely cause more sugar release compared to the storage of wood powder in buffer, but when the pretreated wood was incubated with cellulase the sugar release was higher than without pretreatment. Release of sugar from untreated cellulose in liquid cultures of the white-rot fungusTrametes versicolorwas detected after 7 days and increased linearly with incubation time. Sugar release from DMDHEU-treated cellulose was much lower and was not detectable before 21 days of incubation. Total protein content in the cultures was low, but was slightly higher in the cultures of untreated cellulose. Laccase activity was not different in the presence of untreated and DMDHEU-treated cellulose after 7 and 14 days, but increased with increasing DMDHEU content after 21 and 28 days.

Lignocellulosic wastes such as neem hull, wheat bran, and sugarcane bagasse, available in abundance, are excellent substrates for the production of ligninolytic enzymes under solid-state fermentation by white-rot fungi. A ligninolytic enzyme system with high activity showing enhanced decomposition was obtained by cocultivation of Pleurotus ostreatus and Phanerochaete chrysosporium on combinations of lignocellulosic waste. Among the various substrate combinations examined, neem hull and wheat bran wastes gave the highest ligninolytic activity. A maximum production of laccase of 772 U/g and manganese peroxidase of 982 U/g was obtained on d 20 and lignin peroxidase of 656 U/g on d 25 at 28 +/- 1 degrees C under solid-state fermentation. All three enzymes thus obtained were partially purified by acetone fractionation and were exploited for decolorizing different types of acid and reactive dyes.