Kumar Pranaw

Harnessing the hydrolytic potential of phytopathogenic fungus Phoma exigua ITCC 2049 for saccharification of lignocellulosic biomass

Phytopathogenic fungi develop unique systems for fast invasion by producing hydrolases, which may be explored as a source of hydrolytic enzymes for biofuel research. The present work deals with evaluation of a potato pathogen Phoma exigua ITCC 2049 for its potential to produce cellulase and xylanase enzyme. Taguchi methodology was applied to reveal the influence and contribution of five important factors (carbon source, organic and inorganic nitrogen source, surfactant, and pH) on hydrolytic enzyme production by Phoma. Cultivation of fungus under optimized condition produced endoglucanase (37.00 IU/ml), FPase (1.13 IU/ml), β-glucosidase (2.67 IU/ml) and xylanase (24.92 IU/ml) within 8 days of submerged fermentation. Saccharification of biopretreated Parthenium and paddy straw with cocktail of Phoma secretome supplemented with commercial β-glucosidase resulted in the significantly higher reducing sugar yield (651.04-698.11 mg/gds). This study proves the potential of Phoma as an alternative source of enzymes for biomass saccharification.

Proteomic analysis of Streptomyces sp. ssr‐198 grown on paddy straw

The filamentous bacteria Streptomyces spp. produces diverse extracellular enzymes and other secondary metabolites. Proteomic analysis of the secretome of holocellulolytic Streptomyces sp. ssr‐198 was done by tandem mass spectrometry using an Orbitrap Velos hybrid mass spectrometer. A wide range of hydrolytic enzymes, including glycoside hydrolases (17), proteases (17), polysaccharide lyases (3), esterases (2), and hypothetical proteins (14) were detected in the secretome analyzed. Overall, the secretome composition constituted of 12.50% cellulases, 17.50% hemicellulases, 21.25% proteases, 17.50% hypothetical proteins, and 31.25% other proteins. Comprehensive analysis of secretome will be useful in gaining better understanding of the unique role of hydrolytic enzymes in lignocellulose hydrolysis and helps in determining the industrial applications of these potent enzymes.

Statistical Optimization of Media Components for Production of Fibrinolytic Alkaline Metalloproteases from Xenorhabdus indica KB-3

Xenorhabdus indica KB-3, a well-known protease producer, was isolated from its entomopathogenic nematode symbiont Steinernema thermophilum. Since medium constituents are critical to the protease production, the chemical components of the selected medium (soya casein digest broth) were optimized by rotatable central composite design (RCCD) using response surface methodology (RSM). The effects of all five chemical components (considered as independent variables), namely tryptone, soya peptone, dextrose, NaCl, and dipotassium phosphate, on protease production (dependent variable) were studied, and it was found that tryptone and dextrose had maximum influence on protease production. The protease production was increased significantly by 66.31% under optimal medium conditions (tryptone—5.71, soya peptone—4.9, dextrose—1.45, NaCl—6.08, and dipotassium phosphate—0.47 in g/L). To best of knowledge, there are no reports on optimization of medium component for protease production by X. indica KB-3 using RSM and their application in fibrinolysis. This study will be useful for industrial processes for production of protease enzyme from X. indica KB-3 for its application in the field of agriculture and medicine.

Two‐step statistical optimization for cold active β‐glucosidase production from Pseudomonas lutea BG8 and its application for improving saccharification of paddy straw

β‐Glucosidase is an essential part of cellulase enzyme system for efficient and complete hydrolysis of biomass. Psychrotolerant Pseudomonas lutea BG8 produced β‐glucosidase with lower temperature optima and hence can play important role in bringing down the energy requirement for bioethanol production. To enhance β‐glucosidase production, two statistical tools: Taguchi and Box–Behnken designs were applied to reveal the most influential factors and their respective concentration for maximum production of β‐glucosidase under submerged fermentation. The optimal medium composition for maximum β‐glucosidase production were 2.99% (w/v) bagasse, 0.33% (w/v) yeast extract, 0.38% (w/v) Triton X‐100, 0.39% (w/v) NaNO3, and pH 8.0 at temperature 30 °C. Under optimized conditions, β‐glucosidase production increased up to 9.12‐fold (17.52 ± 0.24 IU/g) in shake flask. Large‐scale production in 7‐L stirred tank bioreactor resulted in higher β‐glucosidase production (23.29 ± 0.23 IU/g) within 80 H of incubation, which was 1.34‐fold higher than shake flask studies. Commercial cellulase (Celluclast® 1.5L) when supplemented with this crude β‐glucosidase resulted in improved sugar release (548.4 ± 2.76 mg/gds) from paddy straw at comparatively low temperature (40 °C) of saccharification. P. lutea BG8 therefore showed great potential for cold active β‐glucosidase production and can be used as accessory enzyme along with commercial cellulase to improve saccharification efficiency.