AbstractChitin is an abundant, linear, insoluble β-1, 4-linked N-acetylglucosamine polymer (GlcNAc), found in the cuticles of insects, the cell walls of fungi and crustacean shells. Chitinases are hydrolytic enzymes which catalyze the breakdown of chitin and are produced by a diverse range of microorganisms, plants, mammals and insects. Microbial chitinases are primarily in charge of breaking down chitin and are essential for maintaining an ecosystem’s balance of carbon and nitrogen. They are gaining ground in the fields of medicine, agriculture, food, pharmaceuticals and environmental management due to their vast range of applications. In contrast to chemical pesticides, they have shown their ability to act as biocontrol agents against a variety of pathogenic fungus and insect pests. Considering the essential role of chitinases as biopesticides and in a variety of industrial and medicinal applications, this review focusses on the basic structure of chitin and chitinases, different classes of chitinases, their sources, purification, characterization and latest developments in implementation of chitinases in various fields such as biomedical, agricultural, environmental, etc.

AbstractSustainable environmental cleanup has become a widespread concept in the era of industrialization and the ever-increasing population. Due to anthropogenic activities, textile industries release a large amount of wastewater into the surrounding water bodies. In this study, a highly efficient bacterial isolate, Bacillus sp. AS2 was isolated from textile dye-contaminated soil. Different growth parameters were studied to enhance the degradation activity of the isolate. Maximum dye degradation achieved was 97.01 ± 0.36%, 92.49 ± 0.21%, and 94.23 ± 0.47% for methylene blue (MB), Congo red (CR), and malachite green (MG), respectively. The isolated bacteria were also capable of degrading (77.76 ± 0.15%) mixed dyes. Fourier-transform infra-red (FTIR) and gas chromatography–mass spectrometry (GC–MS) analysis confirmed the degradation of the textile dyes. The maximum bacterial growth rate was 0.425, 0.578, and 0.512 g d−1 in the presence of MB, CR, and MG dye, respectively. The value of µmax/Ks was 0.0154, 0.0167, and 0.0137 L mg−1 d−1 for MB, CR, and MG dye. Further, the phytotoxicity assay substantiates the eco-friendly nature of isolate Bacillus sp. AS2. Biodegradation through the selected bacterial strain can be considered the best alternative to control environmental pollution in a comparatively short time interval.

AbstractA substantial reduction in the cost of biodiesel production necessitates the identification of less expensive lipid-bearing substrates and a cost-effective process. The present study demonstrates the use of biomass suspension of Aspergillus sps. as a whole-cell catalyst for the generation of various alkyl esters from acid oil and cottonseed oil with different alcohols (methanol to decanol) as acyl acceptors. The yield of alkyl esters increased from methanol (79%) to pentanol (87%), followed by a decrease from hexanol (80%) to decanol (55%) in the case of acid oil. The extent of transesterification was significantly higher [P < 0.05] in case of acid oil, with most of the acyl acceptors as compared to cottonseed oil. The study reveals the potential use of biomass suspension of fungus as a catalyst and acid oil as an alternative, low-cost bearing, and quality feedstock for the generation of biodiesel for a diverse variety of industrial/commercial use.

AbstractThe present work deals with the preparation and characterization of Zn2Al layered double hydroxides (LDHs) intercalated with chloride and dodecyl sulfate ions and their use as supports for the immobilization of Pseudomonas cepacia lipase (LipPS). LipPS was immobilized on LDH by adsorption, in situ entrapment and delamination entrapment methods. The performance of free and immobilized LipPS in the transesterification of (R,S)-1-phenylethanol was compared. The immobilized derivatives prepared by adsorption gave the highest conversions (c = 50%), with an enantiomeric excess of the product (eep) greater than 99% and a high enantiomeric ratio (E > 200). For immobilization by in situ entrapment (coprecipitation), a conversion of 31.5% and E > 200 were obtained. For immobilization by delamination entrapment, a conversion of 36% and E= 155 were obtained. Although the best results were obtained by adsorption, these results show that the delamination entrapment method can also be used to prepare bioinorganic-enzyme materials based on LDH. Our work therefore increases the range of methods that can be used to immobilize lipases for use in the production of optically pure secondary alcohols.

AbstractHigh cost and low operational stability are the most important challenges limiting the possible use of laccase in the removal of textile dyes. To overcome these challenges, in this study, polyvinylpyrrolidone (PVP)-coated magnetic nanoparticles (MNPs) were produced and characterized. To our knowledge, this is the first study to explore the feasibility of immobilizing a Trametes trogii laccase enzyme on Fe3O4/PVP MNPs. The characterization of samples and the successful immobilization of laccase were verified by characterization methods. Besides, the biochemical properties and stability of the Fe3O4/PVP/Lac were evaluated in terms of optimum pH, optimum temperature, thermostability, thermodynamic and kinetic parameters, storage stability, operational stability, and decolorization efficiency of two different textile dyes. The optimum activities were recorded at pH 2.5 °C and 30 °C. The Fe3O4/PVP/Lac displayed remarkable thermal stability and activation energy for denaturation, enthalpy, Gibbs free energy, and entropy results confirmed the enhanced stability of Fe3O4/PVP/Lac against high temperatures. Meanwhile, the Fe3O4/PVP/Lac retained about 58% of its original activity after seven consecutive reuses, while it retained up to 25% of its original activity after 28 d of storage at room temperature. Km and Vmax for the Fe3O4/PVP/Lac were calculated to be 126 µM and 211 µmol/min, respectively. Finally, after 8 and 6 cycles of repeated use, the Fe3O4/PVP/Lac still decolorized 32.34% and 32.23% of Remazol Brilliant Blue R (RBBR) and Indigo Carmine (IC), respectively. As envisioned, this study suggests a promising way to solve the problems of high price and poor operational stability of the enzyme during biocatalytic decolorization of textile dyes in wastewaters.

AbstractHerein, we report the use of whole cells of Brazilian marine-derived fungi in the biotransformation and biodegradation of organic compounds, particularly, Knoevenagel adducts. A preliminary screening with five marine-derived fungi revealed that these microorganisms promoted the bioreduction and biodegradation of four Knoevenagel adducts. Additionally, a biotransformation pathway for these compounds was proposed, which suggested the presence of ene-reductase and alcohol dehydrogenase in the marine-derived fungi, which catalysed the microbial transformation of the substrates. In summary, the fast biodegradation of organic molecules has an ecological relevance since several of these compounds and their biotransformed products have aquatic environment impact.

AbstractIn this study, a Taguchi experimental design was used for optimzing the immobilization of the lipase Eversa® Transform 2.0 (EVS) onto a hybrid support consisting of chitosan (CHI) and agarose (AGA), with glutaraldehyde (GLU) used as the support activator. The biocatalyst obtained was characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TGA), Energy Dispersive Spectroscopy (EDS), and Scanning Electron Microscopy (SEM). The optimized reaction conditions (60 min, 5 mM ionic strength, 1% GLU concentration, and 5 mg protein load per g of support) resulted in a highly active biocatalyst (74.39 ± 0.48 U/g) and delivered an immobilization yield of 74.20 ± 0.28%. The biocatalyst produced was observed to lose only 15.3% of its activity after 61 days of storage. The activity was also observed to increase by 96.70% ± 0.76, 27.34% ± 2.34, and 84.35% ± 1.68 in the presence of the organic solvents hexane, cyclohexane, and methanol, respectively. Additionally, the byocatalist showed more pronounced activity at temperatures above 50 °C and was still able to retain approximately 30% of it at 70 °C. These values were found to be higher at alkaline pHs, as the activity of Eversa® 2.0 Transform saw an increase of up to 140% at pH 9. The desorption tests performed did not reveal any enzymatic detachment from the support. The novel biocatalyst also showed promising ester-lubricating properties. Furthermore, the in silico study revealed a binding affinity of −5.1 kcal/mol between oleic acid and the enzyme, suggesting that the combination of the substrate and the lipase was more stable and therefore, suitable for esterification.

AbstractEnantiomerically pure secondary alcohols are useful in the synthesis of several natural products and as active pharmaceutical intermediates (API). Due to the high demand for these chiral compounds, much progress has been made in the areas of asymmetric synthesis and catalysis. In this context, biocatalysis together with continuous flow technology can be a valuable tool for more versatile and sustainable methods, with lower cost, greater stereoselectivity and less environmental impact. This work aims to obtain an enantiomerically pure alcohol of industrial interest, (4 Fluorophenyl) (furan-2-yl) methanol (3), by performing a kinetic resolution using immobilized Candida antarctica lipase B (Novozyme 435, N435) under continuous-flow conditions. Initial study was carried out to optimize batch reaction conditions. The best results were obtained using isooctane as solvent, 37.7 mg of N435 and three equivalents of isopropenyl acetate as acyl donor at 60 °C for 24 h. Under these conditions, a conversion of 49% and 91 of enantiomeric ratio was obtained. Optimized batch conditions were translated to the continuous flow reactor leading to the desired product in 30 min of residence time, 47% conversion and an enantiomeric ratio of 61.

AbstractPesticides released into the environment have become a danger to the mother earth arousing a worldwide alert to initiate remediation at the point sources of contamination in an ecofriendly way. The recent advances in bioremediation technology using microbial consortium have been found effective for the treatment of pesticides in soil. In this context, the present study evaluates and compares the ability of an assembled bacterial consortium C5 (Staphylococcus warneri CPI 2, Pseudomonas putida CPI 9 and Stenotrophomonas maltophilia CPI 15) to remove chlorpyrifos in soil in its free cells state and immobilized state on wood chips. Chlorpyrifos degradation by C5 was studied via a pot study experiment with completely randomized block design. A comparative analysis of degradation, total microbial count and dehydrogenase activity was performed in soils with and without chlorpyrifos application history and under amendment with a mix of cow dung and mushroom spent as biostimulant. Based on ANOVA results, the treatments T3 and T7, both received immobilized C5 and biostimulant were found to be the best giving complete degradation of 125 mg kg−1 of chlorpyrifos in 30 days. All the studied factors – degradation, microbial count and dehydrogenase activity were higher in the soil with chlorpyrifos exposure history. The results presented here highlight the potential use of wood chip immobilized consortium C5 biostimulated with a mix of cow dung and mushroom spent for remediating chlorpyrifos effectively in contaminated soil.

AbstractBiofuels are obtained from various renewable biological sources and considered suitable alternatives to conventional energy sources in the coming future. Biofuel is deemed essential to bioenergy, which can help achieve the 2030 agenda of United Nations Sustainable Development Goals (UNSDGs). Lignocellulosic materials convert into fermentable sugars by several pre-treatment methods. Several microbial lignocellulolytic enzymes play a significant role in degrading pre-treated lignocellulosic biomass into biofuels. These biomass-degrading enzymes have been screened only from a few cultured microorganisms. These problems related to biomass-degrading enzymes can be solved by screening novel microbial enzymes using metagenomic approaches.

AbstractTyrosinase is an enzyme implicated in fruit ripening and the browning of plant parts exposed to mechanical injury. Tyrosinase has numerous reported biotechnological importance. This enzyme was extracted from the waste peels of Musa cavendish, purified via aqueous two-phase partitioning system (ATPS) and QAE-Sephadex ion-exchange chromatography. The purified tyrosinase was biochemically characterized. Tyrosinase was thereafter immobilized, characterized, and applied in the oxidation of phenols in model wastewaters. After purification, the yield and fold obtained were 23% and 8.0 respectively. The molecular weight of the enzyme was estimated to be 43.0 kDa. The purified enzyme had an optimum pH and temperature of 6.5 and 60 °C respectively. The kcatKm  (M−1s−1) obtained for substrates such as L-DOPA, catechol and pyrogallol were 3.6 × 104, 3.8 × 104 and 1.6 × 104  respectively. The purified enzyme was stable in organic solvents: acetone > ethanol > methanol > n-butanol. Quercetin, ascorbic acid, l-cysteine and arginine were potent inhibitors. The immobilized tyrosinase was more resistant to thermoinactivation than the free enzyme as evidenced by its kinetic (kd, t1/2)  and thermodynamic (ΔGd*, ΔHd*, ΔSd*) characteristics. The immobilized tyrosinase removed 70% of 650-µM phenol after 2 h compared to 50% removal by the free tyrosinase. After six repeated cycles of phenol biodegradation using the immobilized enzyme, about 40% of phenol was removed. The fresh peels of M. cavendish served as a green-based source of relatively thermostable immobilized tyrosinase deployable in large-scale biodegradation of phenol-containing wastewater.

AbstractAlthough trypsin is a protease naturally applicable in many processes, it is still possible to increase its efficiency and forms of use. Processes that increase their resilience to different conditions in the reaction medium can expand and/or refine their range of applications. Its performance in the presence of organic solvents, such as acetonitrile (ACN), has been indicated as a promising way to increase the efficiency of digestion processes, such as in sample treatment for MALDI-MS peptide mapping. The maintenance of the activity of trypsin immobilized on glyoxyl-agarose was herein demonstrated in different temperature and ACN ranges. Compared to the soluble, the immobilized enzyme was able to remain active above 50% ACN, where the soluble trypsin showed no activity. Although low, it was still possible to detect about 7% activity at 70% ACN when immobilized form was used. With 7.5% of ACN, the soluble enzyme has already shown loss of activity. The same only occurred with immobilized trypsin at 20% or more. Although the immobilized enzyme may have lower specific activity compared to the soluble one, as confirmed by the determined kinetic parameters, its possibility of reuse was confirmed, with no loss of activity for 5 cycles at 0% and 5% ACN. Added to this is the simplicity that the reaction can be interrupted, through the removal of the enzyme from the medium. What could prevent its own protein chain from contaminating the final product. With these characteristics added, trypsin in its immobilized form presents itself as a promising biocatalyst.

AbstractPlant biomass is a kind of renewable, abundant, eco-friendly, and clean natural resource. Recent increase in industrial demand, coupled with development and utilization of biocatalysts for utilization and production of high value-added products from plant biomass have attracted numerous research interest. The ester bond, between plant cell wall polysaccharides and ferulic acid (FA), can be hydrolysed by feruloyl esterases (FAE), thereby destroying compactness of lignocellulosic materials, which is beneficial during utilization of biomass resources. This is this research focus. In this article, we reviewed classification, characteristics, and application of FAE from different species, then highlighted the synergistic effect of FAE action with other enzymes. The findings are considered to provide insights into role of FAE in functional research, biochemical properties, and industrial application, especially with focus on processing of lignocellulosic biomass, harnessing hydroxycinnamate from agricultural by-products, and production of biofuels among other industrial uses.

AbstractCellulose is considered to be an alternative form of energy, and has recently gained significance representing millions of dollars for countries that have the opportunity to obtain energy from it. At the same time, cellulosic biomaterials are attractive since they are both cheap and abundant. To use this important resource, its stubborn structure must be broken down. Rumen bacteria are regarded as unique for this job. In this study, 17 cellulolytic bacteria were isolated from rumen samples collected from Erzurum slaughterhouses. Three bacteria (OZ2, OZ5, OZ17) with maximum enzyme activity were identified by sequencing the 16S rRNA gene region. As a result of the sequence analysis, it was determined that isolates belong to Streptomyces ambofaciens OZ2, Cytobacillus oceanisediminis OZ5, and Streptomyces violaceochromogenes OZ17. Then, cellulase production potentials of these identified bacteria were investigated as single and co-cultures. The co-culture of OZ2 and OZ5 demonstrated the best cellulase activity (26 U/mL). As a result of the optimization studies for the co-culture of OZ2 and OZ5, the best culture conditions were 3 g/L yeast extract, 60 h incubation time, pH 6, and temperature 35 °C. Under optimized conditions, the cellulase enzyme activity increased approximately 3.5-fold to 56 U/mL.

AbstractIn this paper, a Serratia marcescens fibrinolytic protease KD was covalently immobilized onto the electrospun prepared glutaraldehyde (GA)-functionalized chitosan/cellulose acetate membrane nanofibres. Enzyme immobilization has been optimized at some conditions such as different GA values, different crosslinking times, different enzyme and pH values, and different times of immobilization. Results exhibited that the optimized immobilization conditions were obtained in 5.0% GA, after 4 h of crosslinking time, after 8 h immobilization time, using 210 mg protein/g support at pH 9.0. Based on these optimal conditions, the best encapsulation yield (EY) and activity recovery (AR) were obtained about 85% and 121.3%, respectively. The immobilized protease showed a 52% enhancement in protease activity than the free protease in pH 10. Furthermore, results displayed that the Vmax values of free and immobilized enzymes towards casein were gained 0.491 and 0.79 µmol/min, respectively. Moreover, the activity of immobilized protease was retained about 75% after incubation at 60 °C for 180 min at pH 9.0, in which the free protease only preserved about 20% of its primary activity. Results exhibited that the protease-NFs kept nearly 73% of its initial activity after three weeks of storage, while the free protease retained about 20% of its initial activity at the same condition. Results showed that the free protease exhibited 31% clot lysis, whereas the immobilized enzyme exhibited 39% clot lysis. The highest hydrolysis value of both proteases was done 17 and 48% after 4 h at 40 °C, respectively. These results indicated that Chit/CA electrospun nanofibres are excellent membranes for protease immobilization with high application in the digestion of protein waste.

AbstractThe area of combining an enzyme and transition metals to catalyse the sequence of reactions in one-pot which improve total conversion and operational stability has seen tremendous growth in recent years. Herein, we describe the synthesis and substrate controlled modification of β-aminocarbonyl using α-amylase enzyme and Pd-based catalyst in the one-pot. Moreover, the chemo-enzymatic approach provides substituted indole derivatives unprecedentedly when isocyanide was used in the reaction. In the second phase, isocyanide was replaced by phenyl boronic acid which in turn provides the substituted amino biaryls in good yield. Next, the feasibility of one-pot chemo-enzymatic approach was proved by employing substituted 2-bromo aniline along with different isocyanide/phenyl boronic acid and obtained the corresponding products in 56–84% isolated yield.

AbstractAn extracellular alkaline protease from Scytalidium thermophilum was produced in a glucose-containing medium supplemented with 5 mM NaCl for 3 days at pH 8.0 and 45 °C. The enzyme was 10-fold purified using ammonium sulfate precipitation followed by ion-exchange chromatography, and its molecular weight was calculated as 80 kDa from SDS-PAGE. The enzyme exhibited optimum activity at pH 8.0 and 60 °C. It was stable at pH and temperature range of 6.0–10.0 and 30–80 °C, respectively. Its half time was 30 h at pH 6.0, 7.0 and 8.0, while those were 22, 16, 8, and 3 h at 50 °C, 60 °C, 70 °C, and 80 °C, respectively. Kinetic parameters including Km (2 ± 0.02 mg/ml), Vmax (18.7 ± 1.5 µmole tyrosine ml−1 min−1), and kcat (2.5 x 103 min−1) were determined using casein. Ca2+ increased the enzyme activity, but it was slightly reduced by EDTA, Triton X-100, Tween 20, and Tween 80. It was active against reducing agents like β-mercaptoethanol but completely inhibited by phenyl methyl sulphonyl fluoride supporting the enzyme belonging to the serine protease family. Chloroform (143%), methanol (138%), and isopropanol (111%) increased the enzyme activity at 5% (v/v), while ethanol (71%) and acetone (81%) moderately reduced the proteolytic activity at the same concentration. Dimethyl sulfoxide (5%, v/v) did not significantly affect the enzyme. The enzyme was compatible with several detergents (1%, w/v), maintaining more than 90% of its original activity in almost all detergents tested. The stability of the enzyme presented against pH, temperature, organic solvents, and detergents indicates its potential use in various industrial applications, especially in peptide synthesis and the laundry industry.

AbstractNatural deep eutectic solvents (NADESs) were investigated for the activity and stability of the laccase enzyme. Laccase was found to be active only in a low amount of choline chloride containing NADESs while it maintained its activity both in high and low amounts of betaine containing NADESs. Rutin, as a flavonoid monomer shows high antioxidant, antibacterial, antiviral and anti-inflammatory properties and these properties are enhanced in the polymerised form. In this study, the organic co-solvent that is conventionally used in the oligomerization of rutin was replaced with two different green solvents, choline chloride-ethylene glycol (1:2 molar ratio) and betaine-mannose (5:2 molar ratio). LC-MS results revealed spontaneous derivatization of rutin as well as the oligomerization of the derivatives besides rutin. The final products were found to have enhanced superoxide radical activity. In this study, enzymatic oligomerization of rutin was investigated for the first time in the presence of eco-friendly green solvents presenting an alternative pathway without any toxic components.

AbstractFast depleting fossil fuel and its associated negative impacts on environment and climate change raising concern over clean fuel and sustainability. Thus, in line scientific community are thinking to have alternative fuels like hydrogen, natural gas, syngas, and biofuels. Furthermore, hydrogen gas is superior among alternative fuels due to its renewable nature, zero emissions, and generate large content of energy during combustion. Researcher cites on various biological methods like bio photolysis of water, dark fermentation, photo-fermentation, and microbial electrolysis cell. However, biohydrogen production from wastewater as substrate is becoming popular due to less energy intensive and sustainable way to fulfil the future energy demands. With rapid increase in industrialization and urbanization will further increase wastewater generation globally. Hence, wastewaters could have huge potential for the green hydrogen production which ultimately provides clean energy, and the low-cost wastewater treatment. Literature reveals that wastewater from various industries like citric acid, cheese whey, paper mill, rice mill, beverage, cassava starch processing, palm oil, starch processing, pharmaceutical, food processing, distillery, and sugar industry have been utilized for biohydrogen production. Hence, the present review is focused on various wastewaters based green hydrogen production which have overall positive impacts on social, economic, and environment for the future generation.

AbstractA comparative study of the ability of Trametes hirsuta laccase isoenzymes to biotransform 17β-oestradiol (3,17β-dihydroxyestra-1,3,5(10)-triene, E2) was carried out. Native major LacA and recombinant minor isoenzymes (rLacC, rLacD, and rLacF) obtained in Penicillium canescens were used. It was found that all the studied isozymes are capable of catalysing the oxidative coupling of E2 in an aqueous medium (22 ± 2 °C, pH 4.5) with the formation of predominantly dimers and trimers. Other concurrently formed products were detected by high-pressure liquid chromatography – high-resolution mass spectrometry (HPLC–HRMS) and characterized, summarizing the overall condensation pathway of E2 in laccases. The highest catalytic activity was observed for major LacA. For other laccases, the activity decreased in the following sequence rLacF > rLacD > rLacC. Utilization of T. hirsuta enzymatic variety of laccases can be of benefit for detoxification of phenol-like steroid compounds in the environment.