A review on bio-based polymer polylactic acid potential on sustainable food packaging.

Poly(lactic acid) (PLA) stands as a compelling alternative to conventional plastic-based packaging, signifying a notable shift toward sustainable material utilization. This comprehensive analysis illuminates the manifold applications of PLA composites within the realm of the food industry, emphasizing its pivotal role in food packaging and preservation. Noteworthy attributes of PLA composites with phenolic active compounds (phenolic acid and aldehyde, terpenes, carotenoid, and so on) include robust antimicrobial and antioxidant properties, significantly enhancing its capability to bolster adherence to stringent food safety standards. The incorporation of microbial and synthetic biopolymers, polysaccharides, oligosaccharides, oils, proteins and peptides to PLA in packaging solutions arises from its inherent non-toxicity and outstanding mechanical as well as thermal resilience. Functioning as a proficient film producer, PLA constructs an ideal preservation environment by merging optical and permeability traits. Esteemed as a pioneer in environmentally mindful packaging, PLA diminishes ecological footprints owing to its innate biodegradability. Primarily, the adoption of PLA extends the shelf life of products and encourages an eco-centric approach, marking a significant stride toward the food industry's embrace of sustainable packaging methodologies.

A comprehensive review of eclectic approaches to the biological synthesis of vanillin and their application towards the food sector.

Vanillin, a highly regarded flavor compound, has earned widespread recognition for its natural and aromatic qualities, piquing substantial interest in the scientific community. This comprehensive review delves deeply into the intricate world of vanillin synthesis, encompassing a wide spectrum of methodologies, including enzymatic, microbial, and immobilized systems. This investigation provides a thorough analysis of the precursors of vanillin and also offers a comprehensive overview of its transformation through these diverse processes, making it an invaluable resource for researchers and enthusiasts alike. The elucidation of different substrates such as ferulic acid, eugenol, veratraldehyde, vanillic acid, glucovanillin, and C6-C3 phenylpropanoids adds a layer of depth and insight to the understanding of vanillin synthesis. Moreover, this comprehensive review explores the multifaceted applications of vanillin within the food industry. While commonly known as a flavoring agent, vanillin transcends this role by finding extensive use in food preservation and food packaging. The review meticulously examines the remarkable preservative properties of vanillin, providing a profound understanding of its crucial role in the culinary and food science sectors, thus making it an indispensable reference for professionals and researchers in these domains.

Advances in enzymatic conversion of biomass derived furfural and 5-hydroxymethylfurfural to value-added chemicals and solvents.

The progress of versatile chemicals and bio-based fuels using renewable biomass has gained ample importance. Furfural and 5-hydroxymethylfurfural are biomass-derived compounds that serve as the cornerstone for high-value chemicals and have a myriad of industrial applications. Despite the significant research into several chemical processes for furanic platform chemicals conversion, the harsh reaction conditions and toxic by-products render their biological conversion an ideal alternative strategy. Although biological conversion confers an array of advantages, these processes have been reviewed less. This review explicates and evaluates notable improvements in the bioconversion of 5-hydroxymethylfurfural and furfural to comprehend the current developments in the biocatalytic transformation of furan. Enzymatic conversion of HMF and furfural to furanic derivative have been explored, while the latter has substantially overlooked a foretime. This discrepancy was reviewed along with the outlook on the potential usage of 5-hydroxymethylfurfural and furfural for the furan-based value-added products' synthesis.

Designing a novel poly (methyl vinyl ether maleic anhydride) based polymeric membrane with enhanced antifouling performance for removal of pentachlorophenol from aqueous solution.

In this current study, poly (methyl vinyl ether maleic anhydride) (PMVEAMA), a sustainable additive, was incorporated into poly (ether-ether sulfone) (PEES) polymer to design a novel polymeric hybrid membrane for the efficient filtration of toxic pentachlorophenol (PCP) from an aqueous medium. Hydrophilic additives significantly altered the membrane's morphology, structure, porosity, water content, and flux performance compared to the bare PEES membrane. The influence of PMVEAMA on the structural modification of the synthesized polymer membrane was confirmed by SEM, ATR-FTIR, XRD, AFM, zeta potential and contact angle. Findings revealed that the addition of PMVEAMA to the PEES polymer enhances the porosity (17.7%-28.9%), water content (29.8%-39.8%), and pure water flux (186 Lm-2h-1 to 349 Lm-2h-1). The effect of PMVEAMA concentration on the PEES membrane exhibited more finger like pores, better porosity and hydrophilicity, reduced surface roughness, fouling and increased permeability. The fouling studies exhibit an improved 57% PCP rejection and permeation flux of 22.3 Lm-2h-1 due to the addition of the hydrophilic additive. Surprisingly, the incorporation of PMVEAMA into the bare PEES membrane resulted in a high flux recovery ratio of 73.7%. The antifouling properties and enhanced permeability of the PEES/PMVEAMA membrane indicates its potential application in water purification sectors for the efficient separation of contaminants.

Coimmobilized enzymes as versatile biocatalytic tools for biomass valorization and remediation of environmental contaminants - A review.

Due to stringent regulatory norms, waste processing faces confrontations and challenges in adapting technology for effective management through a convenient and economical system. At the global level, attempts are underway to achieve a green and sustainable treatment for the valorization of lignocellulosic biomass as well as organic contaminants in wastewater. Enzymatic treatment in the environmental aspect thrived on being the promising rapid strategy that appeased the aforementioned predicament. On that account, coimmobilization of various enzymes on single support enhances the catalytic activity ensuing operational stability with industrial applications. This review pivoted towards the coimmobilization of enzymes on diverse supports and their applications in biomass conversion to industrial value-added products and removal of contaminants in wastewater. The limelight of this study chronicles the unique breakthroughs in biotechnology for the production of reusable biocatalysts, which inculcating various enzymes towards the scope of environment application.

Laccase production by Pleurotus ostreatus using cassava waste and its application in remediation of phenolic and polycyclic aromatic hydrocarbon-contaminated lignocellulosic biorefinery wastewater.

The treatment of contaminants from lignocellulosic biorefinery effluent has recently been identified as a unique challenge. This study focuses on removing phenolic contaminants and polycyclic aromatic hydrocarbons (PAHs) from lignocellulosic biorefinery wastewater (BRW) applying a laccase-assisted approach. Cassava waste was used as a substrate to produce the maximum yield of laccase enzyme (3.9 U/g) from Pleurotus ostreatus. Among the different inducers supplemented, CuSO4 (0.5 mM) showed an eight-fold increase in enzyme production (30.8 U/g) after 240 h of incubation. The catalytic efficiency of laccase was observed as 128.7 ± 8.47 S-1mM-1 for syringaldazine oxidation at optimum pH 4.0 and 40 °C. Laccase activity was completely inhibited by lead (II) ion, mercury (II) ion, sodium dodecyl sulphate, sodium azide and 1,4 dithiothretiol and induced significantly by manganese (II) ion and rhamnolipid. After treating BRW with laccase, the concentrations of PAHs and phenolic contaminants of 1144 µg/L and 46160 µg/L were reduced to 96 µg/L and 16100 µg/L, respectively. The ability of laccase to effectively degrade PAHs in the presence of different phenolic compounds implies that phenolic contaminants may play a role in PAHs degradation. After 240 h, organic contaminants were removed from BRW in the following order: phenol >2,4-dinitrophenol > 2-methyl-4,6-dinitrophenol > 2,3,4,6-tetrachlorophenol > acenaphthene > fluorine > phenanthrene > fluoranthene > pyrene > anthracene > chrysene > naphthalene > benzo(a)anthracene > benzo(a)pyrene > benzo(b)fluoranthene > pentachlorophenol > indeno(1,2,3-cd)pyrene > benzo(j) fluoranthene > benzo[k]fluoranthène. The multiple contaminant remediation from the BRW by enzymatic method, clearly suggests that the laccase can be used as a bioremediation tool for the treatment of wastewater from various industries.

Mycoremediation of lignocellulosic biorefinery sludge: A reinvigorating approach for organic contaminants remediation with simultaneous production of lignocellulolytic enzyme cocktail.

This research work aims to valorize lignocellulosic biorefinery sludge with genetically engineered Trichoderma atroviride for simultaneous removal of organic contaminants, fermentation inhibitors, and lignocellulolytic enzyme cocktail production. Upon analysis, three phenolic compounds (42.6 ± 3.6 µg/g), two polycyclic aromatic hydrocarbons (0.42 ± 0.06 µg/g) and five fermentation inhibitors (2.5 ± 0.3 mg/g) were detected in the sludge. Bioaugmentation of sludge with 72 h-old T. atroviride (5%) results in the production of cellulase (21 U/g), xylanase (84 U/g), laccase (20 U/g), lignin peroxidase (14 U/g) and aryl alcohol oxidase (116 U/g), along with the concomitant removal of organic contaminants (phenol, 2, 4-dinitrophenol, pentchlorophenol, phenanthrene, benzo(a)pyrene) and fermentation inhibitors (furfural, 5-hydroxymethylfurfural, levulinic acid, ferulic acid, and catechol). Subsequently, the enrichment of sludge with nutrients and rhamnolipids enhanced the enzyme production by 5-6-fold and resulted in the removal of 85-95% of organic contaminants and fermentation inhibitors, which constitutes an eco-friendly process.

Surfactant-aided mycoremediation of soil contaminated with polycyclic aromatic hydrocarbons.

Remediation of persistent polycyclic aromatic hydrocarbons (PAHs) contaminated soil has become a major challenge in recent years. Further, conventional application of bioaugmentation strategies for PAHs remediation require continuous supply of microbial specific nutrients, which makes these processes less feasible. Hence, the present study focused on PAHs remediation using surfactants along with wood assisted fungal system in a microcosm set up. In this study, in absence of surfactants, a saturation in PAHs degradation was noted in bioaugmentation with wood assisted fungal system (BAW) with 61 ± 1.25% degradation, followed by bioaugmentation with free fungi system (BAF) (54 ± 0.46%). However, with addition of 1500 mg/L of surface-active compounds (SAC), a maximum PAHs degradation in BAW (100%) and BAF (86 ± 1.30%) strategies were noted on 21st day. Irrespective of the strategies, presence of SAC and rhamnolipids enhanced PAHs degradation by increasing the enzymes production in Trametes hirsuta when compared to Triton x-100 and sodium dodecyl sulphate (SDS). Among the detected PAHs, 100% degradation within 17 days was noted for naphthalene and acenaphthene in SAC-supplemented BAW system. Further, ecotoxicity analysis established showed the LC50 of sediment soil at 26.5 ± 0.24%, which was reduced by an average of 71% after soil remediation. Hence, the current microcosm system proved that the application of SAC with BAW enhanced the PAHs remediation rate, which supports its application in real time soil remediation.

Development of a sustainable route for the production of high-fructose syrup from the polyfructan inulin.

The authors used mesoporous silica microspheres as a support for the immobilization of inulinase from Aspergillus brasiliensis MTCC 1344 by the process of cross-linking. Under optimized operating conditions of pH 6.0, particle/enzyme ratio of 2.0:1.0 and glutaraldehyde concentration of 7 mM, a maximum immobilization yield of 90.7% was obtained after a cross-linking time of 12.25 h. Subsequently, the cross-linked inulinase was utilized for the hydrolysis of 5% inulin, and a maximum fructose concentration of 31.7 g/L was achieved under the optimum conditions of pH 6.0 and temperature 60°C in 3 h. Furthermore, on performing reusability studies during inulin hydrolysis, it was observed that the immobilized inulinase could be reused up to 10 subsequent cycles of hydrolysis, thus providing a facile and commercially attractive process of high-fructose syrup production.

Development of a magnetically separable co-immobilized laccase and versatile peroxidase system for the conversion of lignocellulosic biomass to vanillin.

Lignin obtained from renewable biomass is a potential feedstock for the synthesis of various value-added chemicals through efficient biocatalytic routes. The ligninolytic enzymes-assisted depolymerization of lignin to vanillin constitutes the most commercially attractive and promising approach in green chemistry as vanillin constitutes the second most prevalent flavoring agent. Thus, in the present work, immobilized laccase and versatile peroxidase, and further, a co-immobilized laccase and versatile peroxidase system on magnetic silica microspheres (MSMS) were developed to generate a robust biocatalytic system that mediates the depolymerization of lignin obtained from Casuarina equisetifolia biomass. The depolymerization of lignin by free and immobilized laccase showed a vanillin yield of 24.8% and 23%, respectively, at pH 4.0 in 6 h at 30°C against a vanillin yield of 20% and 21.7% with the free and immobilized versatile peroxidase, respectively, at pH 5.0°C and 50°C. Comparatively, the system with the co-immobilized laccase and versatile peroxidase exhibited a 1-fold and 1.2-fold higher vanillin yield than the free and immobilized laccase system, respectively. On comparing with the versatile peroxidase system, the co-immobilized biocatalytic system displayed 1.3-fold and 1.2-fold increased vanillin yield than the free and immobilized versatile peroxidase system, respectively, at a pH of 6.0 in 6 h at 30°C with an enzyme concentration of 1 U/ml. The reusability studies of the co-immobilized biocatalytic system exhibited that both the enzymes retained up to 40% of its activity till sixth cycle. Implications: The waste biomass of Casuarina equisetifolia is widely available around the coastal regions of India which does not have any agricultural or industrial applications. The present work exploits the lignocellulosic content of the Casuarina biomass to extract the lignin, which provides a renewable alternative for the production of the commercially high-valued compound, vanillin. This work also integrates a co-immobilized biocatalytic process comprising of laccase and versatile peroxidase leading to an environmentally benign enzymatic process for the depolymerization of lignin to vanillin.

Simultaneous pretreatment and saccharification process for fermentable sugars production from Casuarina equisetifolia biomass using transgenic Trichoderma atroviride.

With the increase in the cognizance toward the wide and abundant lignocellulosic biomass, a great interest has been garnered toward the production of value-added products from the biomass. Hence, by capitalizing the Casuarina equisetifolia biomass, the current work developed a simultaneous pre-treatment and saccharification (SPS) process using transgenic Trichoderma atroviride. The ability of T. atroviride to produce lignolytic and cellulolytic enzymes was enhanced by optimizing key process parameters. Under the optimized conditions, a maximum of 1245.6 U/kg of cellulase and 1203.36 U/kg of xylanase, 183.2 U/kg of laccase along with 392.36 g/kg of fermentable sugars were obtained. On comparing with acid and alkaline pre-treatment methods, the T. atroviride -mediated SPS process exhibited trace formation of fermentative inhibitors, which resulted in a minimal inhibition of Escherichia coli. Overall, the current work implements the biorefinery concept on Casuarina equisetifolia biomass by advocating circular economy. Implications: Valorization of lignocellulosic waste biomass into value added compound and as biofuel is considered as a promising alternative resource, owing to its availability and low production cost. However, the presence of chemically resistant lignin demands an intensive treatment process, which sometimes leads to the formation of fermentative inhibitors. Casuarina equisetifolia is a deciduous commercial plant, and an average of 125 tonnes/hector of waste is generated annually in India. By considering the demerit of delignification and the wide availability of Casuarina equisetifolia biomass (CB), the current work aimed at the development of a single-pot simultaneous pre-treatment and saccharification (SPS) of CB by transgenic Trichoderma atroviride.

A comparative study on the chemo-enzymatic upgrading of renewable biomass to 5-Hydroxymethylfurfural.

5-hydroxymethylfurfural (HMF) obtained from renewable biomass-derived carbohydrates is a potential sustainable substitute to petroleum-based building blocks. In the present work, we constituted a comparative study on the production of HMF from two widely available real biomasses in India- Agave americana and Casuarina equisetifolia. In the initial hydrolysis studies for the production of reducing sugars, 649.5 mg/g of fructose was obtained from the hydrolysis of 5% (w/v) A. americana biomass by the enzyme inulinase in 3 h at 50°C. Similarly, upon hydrolysis of 15% (w/v) C. equisetifolia biomass by the lignocellulolytic enzymes (laccase, cellulase and xylanase) from Trichoderma atroviride, 456.65 mg/g of reducing sugars was released in 24 h at 30°C. Subsequently, the dehydration of the obtained reducing sugars to HMF was achieved with titanium dioxide as the catalyst. The dehydration of A. americana-derived fructose at 140°C led to a maximum HMF yield of 92.6% in 15 min with 10% catalyst load. Contrarily, upon optimizing the process parameters for dehydration of C. equisetifolia derived reducing sugars, the maximum HMF yield of 85.7% was obtained at 110°C in 25 min with a TiO2 concentration of 10%. This study reports for the first time the utilization of C. equisetifolia biomass for HMF production and thus, by utilizing these inexpensive, abundantly available and highly functionalized polysaccharides, a strategical approach can be developed for the production of fine chemicals, eliminating the need of fossil-based chemicals. Implications: The catalytic upgrading of lignocellulosic biomass into high-valued platform chemicals like 5-Hydroxymethylfurfural (HMF) implies an extremely significant challenge to the attempts of establishing a green economy. Casuarina equisetifolia and Agave americana represents a sustainable feedstock for the production of HMF through catalytic integration. The present work describes a two-step reaction process where the initial depolymerization step comprises of an enzymatic hydrolysis followed by a chemical-catalyst mediated dehydration process. The utilization of a biocatalytic approach followed by mild chemical catalyst eliminates the need of hazardous chemical conversion processes. Thus, the HMF produced via sustainable can bridge the gap between carbohydrate chemistry and petroleum-based industrial chemistry because of the wide range of chemical intermediates and end-products that can be derived from this compound.

Fabrication of novel amine-functionalized magnetic silica nanoparticles for toxic metals: kinetic and isotherm modeling.

In this research, an amine-functionalized magnetic silica nanosorbent was prepared using the co-precipitation technique, and this nanosorbent can be effortlessly detached using an external magnetic field. FTIR and SEM analyses identified that the nanosorbent holds extraordinary adsorption characteristics for toxic metals' (copper, cadmium, zinc, and nickel) removal. The adsorption-affecting parameters were optimized, and the thermodynamic studies assessed that the adsorption process seemed to be spontaneous, feasible, and exothermic. The pseudo-first-order and Freundlich models perfectly fit the kinetic and equilibrium data, respectively. Langmuir monolayer capacity of the nanosorbent was analyzed using nonlinear evaluation methods such as 419.9 mg/g for copper, 321.9 mg/g for nickel, 217.3 mg/g for cadmium, and 137.6 mg/g for zinc. The used adsorbent was simply rejuvenated using the 0.2 N HCl solution subsequently with intense agitation. The result of the present research confirms that the produced nanosorbent can be effectively utilized for industrial wastewater management.

Immobilized inulinase: a new horizon of paramount importance driving the production of sweetener and prebiotics.

In recent times, inulinase has emerged as one the most prominent and industrially upcoming enzymes applied to meet the ever increasing demand of d-fructose and fructooligosaccharides (FOS) as sweetener and prebiotics in the food and pharmaceutical industry, respectively. This review deals with types of inulinase and the attempts made to modify it for better thermal stability and shelf life. The ease of immobilization of inulinase has led us to the path of experimenting with different methods of enzyme immobilization since 1979. Several modes of immobilization ranging from simple cross-linking of enzymes onto a polymer support to nanoparticles have been applied over the years. The approach and concept of this review provide a yet unexplored focus on pioneering advances for the development of white biotechnology, for instance production of immobilized inulinase-based reusable biocatalysts and bioreactors designed for their use and for the continuous production of fructose and FOS.

Synergetic integration of laccase and versatile peroxidase with magnetic silica microspheres towards remediation of biorefinery wastewater.

In this study, a tailor-made biocatalyst consisting of a co-immobilized lignolytic enzyme cascade on multi-functionalized magnetic silica microspheres (MSMS) was developed. Physical adsorption was the most promising strategy for the synthesis of individual immobilized laccase (IL), immobilized versatile peroxidase (IP), as well as co-immobilized laccase (Lac) and versatile peroxidase (VP) with an enzyme activity recovery of about 79, 93, 27, and 27.5%, respectively. Similarly, the biocatalytic load of 116, 183, 23.6, and 31 U/g was obtained for IL, IP, and co-immobilized Lac and VP, respectively. The co-immobilized enzyme system exhibited better pH stability than the free and individual immobilized system by retaining more than 100% residual activity at pH 7.0 after a 150-h incubation; whereas, the thermal stability and kinetics of the co-immobilized biocatalyst were not much improved. IL and IP could be recycled for 10 cycles after which they retained 31 and 44% of their initial activities. Co-immobilized Lac and VP were reused for ten consecutive cycles at the end of which Lac activity was depleted, and 37% of VP activity was left. Free enzymes, IL, IP, co-immobilized Lac, and VP were applied to biorefinery wastewater (BRW) in a batch study to investigate the transformation of phenolic contaminants over a period of 5 days. The major classes of phenolic constituents in terms of their order of removal in a Lac-VP system was phenol >2-chlorophenol > trichlorophenol > dichlorophenol > cresols > dimethylphenol >2 methyl- 4, 6-dinitrophenol > 4-nitrophenol > tetrachlorophenols > pentachlorophenol. The free enzymes and individually immobilized enzymes resulted in 80% dephenolization in 5 days. By contrast, the co-immobilized biocatalyst provided rapid dephenolization yielding the same 80% removal within 24 h and 96% removal of phenols in 60 h after which the system stabilized, which is the major advantage of the co-immobilized biocatalyst. ᅟ Graphical abstract.

Simple screening protocol for identification of potential mycoremediation tools for the elimination of polycyclic aromatic hydrocarbons and phenols from hyperalkalophile industrial effluents.

A number of fungal strains belonging to the ascomycota, basidiomycota and zygomycota genera were subjected to an in vitro screening regime to assess their ligninolytic activity potential, with a view to their potential use in mycoremediation-based strategies to remove phenolic compounds and polycyclic aromatic hydrocarbons (PAHs) from industrial wastewaters. All six basidiomycetes completely decolorized remazol brilliant blue R (RBBR), while also testing positive in both the guaiacol and gallic acid tests indicating good levels of lignolytic activity. All the fungi were capable of tolerating phenanthrene, benzo-α- pyrene, phenol and p-chlorophenol in agar medium at levels of 10 ppm. Six of the fungal strains, Pseudogymnoascus sp., Aspergillus caesiellus, Trametes hirsuta IBB 450, Phanerochate chrysosporium ATCC 787, Pleurotus ostreatus MTCC 1804 and Cadophora sp. produced both laccase and Mn peroxidase activity in the ranges of 200-560 U/L and 6-152 U/L, respectively, in liquid media under nitrogen limiting conditions. The levels of adsorption of the phenolic and PAHs were negligible with 99% biodegradation being observed in the case of benzo-α-pyrene, phenol and p-chlorophenol. The aforementioned six fungal strains were also found to be able to effectively treat highly alkaline industrial wastewater (pH 12.4). When this wastewater was supplemented with 0.1 mM glucose, all of the tested fungi, apart from A. caesiellus, displayed the capacity to remove both the phenolic and PAH compounds. Based on their biodegradative capacity we found T. hirsuta IBB 450 and Pseudogymnoascus sp., to have the greatest potential for further use in mycoremediation based strategies to treat wastestreams containing phenolics and PAHs.

Xenobiotic Compounds Degradation by Heterologous Expression of a Trametes sanguineus Laccase in Trichoderma atroviride.

Fungal laccases are enzymes that have been studied because of their ability to decolorize and detoxify effluents; they are also used in paper bleaching, synthesis of polymers, bioremediation, etc. In this work we were able to express a laccase from Trametes (Pycnoporus) sanguineus in the filamentous fungus Trichoderma atroviride. For this purpose, a transformation vector was designed to integrate the gene of interest in an intergenic locus near the blu17 terminator region. Although monosporic selection was still necessary, stable integration at the desired locus was achieved. The native signal peptide from T. sanguineus laccase was successful to secrete the recombinant protein into the culture medium. The purified, heterologously expressed laccase maintained similar properties to those observed in the native enzyme (Km and kcat and kcat/km values for ABTS, thermostability, substrate range, pH optimum, etc). To determine the bioremediation potential of this modified strain, the laccase-overexpressing Trichoderma strain was used to remove xenobiotic compounds. Phenolic compounds present in industrial wastewater and bisphenol A (an endocrine disruptor) from the culture medium were more efficiently removed by this modified strain than with the wild type. In addition, the heterologously expressed laccase was able to decolorize different dyes as well as remove benzo[α]pyrene and phenanthrene in vitro, showing its potential for xenobiotic compound degradation.

Towards high potential magnetic biocatalysts for on-demand elimination of pharmaceuticals.

The present study investigated the applicability of a laccase based bioprocess for the treatment of a mixture containing 13 selected pharmaceuticals. To do so, laccase was immobilized as cross-linked enzyme aggregates (MAC-CLEAs) on amine functionalized magnetic nanoparticles using chitosan/1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDAC) as the cross-linking system. The activity recovery of laccase reached 61.4% under the optimal conditions of MAC-CLEAs formation. The latter exhibited enhanced storage stability over one year at 4°C and showed better temperature resistance compared to its soluble counterpart. The biocatalysts were properly recycled and the catalytic activity recovery was good even after a hundred and fifty batch reactions. Complete removal of pharmaceuticals like acetaminophen, diclofenac, mefenamic acid, atenolol and epoxy carbamazepine and partial removal of fenofibrate, diazepam, trimethoprim, and ketoprofen by laccase was achieved within 12h of incubation, whereas efficient removal of indometacin required the presence of mediator.

Magnetic cross-linked laccase aggregates--bioremediation tool for decolorization of distinct classes of recalcitrant dyes.

The increasing use of laccase in waste water industries is useful to explore the high benefit/cost ratio of insolubilization technologies like cross linked enzyme aggregates (CLEAs) for the decolorization and detoxification of distinctive classes of recalcitrant dyes. Amino-functionalized magnetic nanoparticles bonded to CLEAs increased the potential of laccase-based CLEAs and are applicable for commercial implementation of this technology in environmental applications. The activity recovery obtained from the stable rigid structure of magnetic CLEAs was around 32%. High volumetric activity, increased in thermal and operational stability of laccase and its resistance to extreme conditions were the properties provided by these magnetic CLEAs. Kinetic studies show that the catalytic efficiency of the enzyme, based on the kcat/km value, changed significantly upon CLEAs and magnetic CLEA formations. When 0.2U/mL of magnetic CLEAs was used, the biocatalyst rapidly decolorized 61-96% of remazol brilliant blue R, malachite green and reactive black 5 initially at 50mgL(-1) at 20°C and pH7.0. Investigation of dye degradation using both active and heat denatured CLEAs revealed a slight adsorption of dyes on inactivated biocatalysts. A laboratory scale perfusion basket reactor (BR) was used to study the continuous decolorization of dyes. The efficient decolorization (>90%) of remazol brilliant blue R and slight decrease in CLEA activity were measured over a 10h period of continuous operation, which illustrates the potential of CLEAs for the wastewater treatment. The present findings will advance the understanding of dye decolorization mechanism by CLEA laccase, which could provide useful references for developing industrial wastewater treatment.

Chemometric formulation of bacterial consortium-AVS for improved decolorization of resonance-stabilized and heteropolyaromatic dyes.

A bacterial consortium-AVS, consisting of Pseudomonas desmolyticum NCIM 2112, Kocuria rosea MTCC 1532 and Micrococcus glutamicus NCIM 2168 was formulated chemometrically, using the mixture design matrix based on the design of experiments methodology. The formulated consortium-AVS decolorized acid blue 15 and methylene blue with a higher average decolorization rate, which is more rapid than that of the pure cultures. The UV-vis spectrophotometric, Fourier transform infra red spectrophotometric and high performance liquid chromatographic analysis confirm that the decolorization was due to biodegradation by oxido-reductive enzymes, produced by the consortium-AVS. The toxicological assessment of plant growth parameters and the chlorophyll pigment concentrations of Phaseolus mungo and Triticum aestivum seedlings revealed the reduced toxic nature of the biodegraded products.