Extraction of chitosan from biologically-derived chitin by bacterial chitin deacetylase: Process optimization and product quality assessment.

Commercial chitosan manufacturing process relies on strong chemical treatment on chitin that generates chitosan with undesirable properties and leads to environmental pollution. To overcome the adverse consequences, enzymatic chitosan preparation from chitin was undertaken in the current study. A potent chitin deacetylase (CDA) producing bacterial strain was screened and subsequently identified as Alcaligens faecalis CS4. After optimization 40.69 U/mL of CDA production was achieved. By treating the organically extracted chitin with partially purified CDA chitosan yield of 19.04 % was attained having 71 % solubility, 74.9 % degree of deacetylation, 21.16 % crystallinity index, 246.4 kDa molecular weight and 298 °C highest-decomposition temperature. FTIR and XRD analysis revealed characteristics peaks respectively within 870-3425 cm-1 wavenumber and 10°-20°, for enzymatically and chemically extracted (commercial) chitosan that endorses their structural similarity which validated through electron microscopic study. At 10 mg/mL chitosan concentration 65.49 % DPPH radical scavenging activity endorsed its antioxidant potential. Minimum inhibitory concentration of chitosan was 0.675, 1.75, 0.33 and 0.75 mg/mL for Streptococcus mutans, Enterococcus faecalis, Escherichia coli and Vibrio sp., respectively. Mucoadhesiveness and cholesterol binding properties were also exhibited by extracted chitosan. The present study opens a new vista for eco-friendly extraction of chitosan from chitin that is proficient and sustainable in environmental perspective.

Biodeinking of waste papers using combinatorial fungal enzymes and subsequent production of butanol from effluent.

The present study aimed to enzymatic deinking of waste papers and to valorize the effluent for biobutanol production. Application of fungal enzymatic cocktail (cellulase, amylase, xylanase, pectinase, lipase, and ligninase) on office used paper, newspaper, and ballpen written paper leading to improvement in brightness (84.91, 72.51, 76.69 % ISO), InKd (82.89, 68.95, 76.49%), κ-number (12.9, 13.6, and 13.1), opacity (27.91, 30.07, and 2.85%), tensile strength (49.24, 45.31, and 46.98 Nm/g), respectively and indices were consistent with chemical treated pulps. The quality of effluent generated during enzymatic deinking in respect to BOD and COD level was eco-friendlier than the chemical process. The enzyme-treated effluent was employed as supporting substrate for butanol (18.4 g/l) production by Clostridium acetobutylicum ATCC824. Material balance and life cycle assessment of the whole processes were evaluated to validate its industrial and environmental relevance.

Saccharification of lignocellulosic biomass using an enzymatic cocktail of fungal origin and successive production of butanol by Clostridium acetobutylicum.

A multistep approach was undertaken for biobutanol production targeting valorization of agricultural waste. Optimum production of lignocellulolytic enzymes [CMCase (3822.93U/mg), FPase (3640.93U/mg), ß-glucosidase (3873.92U/mg), xylanase (3460.24U/mg), pectinase (3359.57U/mg), α-amylase (4136.54U/mg), and laccase (3863.16U/mg)] was accomplished through solid-substrate fermentation of pretreated mixed substrates (wheat bran, sugarcane bagasse and orange peel) by Aspergillus niger SKN1 and Trametes hirsuta SKH1. Partially purified enzyme cocktail was employed for saccharification of the said substrate mixture into fermentable sugar (69.23 g/L, product yield of 24% w/w). The recovered sugar with vegetable extract supplements was found as robust fermentable medium that supported 16.51 g/L biobutanol production by Clostridium acetobutylicum ATCC824. The sequential bioprocessing of low-priced substrates and exploitation of vegetable extract as growth factor for microbial butanol production will open a new vista in biofuel research.

Extraction of chitin from Litopenaeus vannamei shell and its subsequent characterization: an approach of waste valorization through microbial bioprocessing.

Chemical extraction of chitin is very hazardous and costly which can be overwhelmed by microbial bioprocessing. In this study, potent protease and lactic acid-producing bacteria were screened and identified as Alcaligens faecalis S3 and Bacillus coagulans L2, respectively. Productions of protease and lactic acid by the respective bacterial strains were optimized. The shell of Litopenaeus vannamei was sequentially treated with the partially purified protease and lactic acid and the treatment conditions were optimized for betterment of chitin yield. Spectral characterization by SEM-EDS, IR, XRD, NMR, XPS and thermal characterization by TG and DTG analysis of the extracted chitin was made and compared with commercial one. It was revealed that both the chitin have similar characteristics. Therefore, it can be articulated that chitin can be extracted from crustacean shells in pure form by microbial bioprocessing which will be a good catch for biorefinary industries for chitin extraction through greener route.

Microbial decomposition of crustacean shell for production of bioactive metabolites and study of its fertilizing potential.

Crustacean shell waste disposal is considered as biggest problem in seafood processing centers. Incineration and landfilling are the commonest ways of disposal of the waste which causes environmental pollution. Microbial bio-conversion is one of the promising approaches to minimize the wastes by utilizing the same for deriving different value added metabolites. In this perspective, chitinase- and protease-producing bacterial strains were isolated from shrimp culture pond, and the potent isolate was subsequently identified as Alcaligenes faecalis SK10. Fermentative optimization of the production of chitinase (85.42 U/ml), protease (58.57 U/ml), and their catalytic products, viz., N-acetylamino sugar (84 µg/ml) and free amino acids (112 µg/ml), were carried out by utilizing shrimp and crab shell powder as principal substrate. The fermented hydrolysate (FH) was subsequently applied to evaluate its potential to be a candidate fertilizer for the growth of leguminous plant Pisum sativum and Cicer arietinum, and the results were compared with chitin, chitosan, and commercial biofertilizer amended group. The results revealed that FH have paramount potential to improve plants morpho-physiological parameters like stem and root length, chlorophyll, cellular RNA, protein content, and soil physico-chemical parameters like total nitrogen, magnesium, calcium, phosphorus, and potassium significantly (p < 0.05). Moreover, the application of FH also selectively encouraged the growth of free-living nitrogen-fixing bacteria, Rhizobium, phosphate-solubilizing bacteria in the soil by 4.82- and 5.27-, 5.57- and 4.71, and 7.64- and 6.92-fold, respectively, in the rhizosphere of P. sativum and C. arietinum, which collectively is a good sign for an ideal biofertilizer. Co-supplementation of FH with commercial PGPR-biofertilizer significantly influenced the morpho-physiological attributes of plant and physico-chemical and microbial attributes of soil. The study validated proficient and sustainable utilization of fermented hydrolysate of waste crustacean shell as biofertilizer.