ABSTRACT
Aim: The aim of the present study was to evaluate the retting of jute (Corchorus olitorius L. and C. capsularis L.) using the endospores of microbial consortium of three strains of Bacillus pumilus with extended shelf-life. Methodology: Endospore and vegetative cells of Bacillus pumilus were tested for viability by introducing them into different temperature, pH, UV radiation and antibiotics. Laboratory, as well as field-trials of jute retting was performed with 6 and 18-months-old endospores and vegetative cells of Bacillus pumilus with estimation of enzymatic activities for comparison of their retting efficiency. Results: Endospores of Bacillus pumilus recorded very high colony forming unit (109 to 108ml-1) compared to their vegetative cells (106 to 104ml-1) after 6 to 18 months of their preservation. Endospores also showed higher resistance to temperature, pH, UV irradiation and antibiotic than their vegetative forms. High colony forming unit and higher release of pectinolytic and xylanolytic enzymes during retting of jute by endospores resulted in complete of jute retting in 10 days with good quality jute fibre compared to talc based formulation. Interpretation: It can be concluded from the study that endospores remained highly efficient in rejuvenating higher CFU and quantitatively larger pool of enzymes to accelerate retting of jute after prolonged preservation. Therefore, the endospores of Bacillus pumilus can be used cost effectively in place of their talc based formulation for higher shelf life of the product, faster retting and better fibre quality of jute.
ABSTRACT
The retting environment which provides a competitive niche for specialized microbes is speculated to harbour a variety of microbes with high biodegradation potential. In this context, an effort has been made to isolate and identify bacterial species having high tolerance to phenol In vitro. Maximum polyphenol (1.897 mg l-1 ) as observed during the initial period of retting, which decreased as retting proceeded. Based on biochemical characterization, the isolated bacterial strains were identified as Micrococcus sp., Moraxella sp. strain MP1, Moraxella sp. strain MP2 and Moraxella sp. strain MP3, Pseudomonas sp. strain PP1 and Pseudomonas sp. strain PP2, Amphibacillus sp., Brucella sp. strain BP1 and Brucella sp. strain BP2, Aquaspirillum sp., Escherichia coli strain EP1 and Escherichia coli strain EP2, Campylobacter sp., Aeromonas sp., Neisseria sp., Vibrio sp., Erwinia sp. and Mesophilobacter sp. These strains were found to tolerate maximum concentration of phenol viz. 200 to 1000 mg l-1. Plasmid analysis of phenol resistant bacterial isolates showed that almost all the cultures had at least one plasmid of size >1Kb. Studies on the protein profile of isolated bacterial cultures showed the presence of proteins with molecular sizes ranging from 10 to 85 KDa with exception of Mesophilobacter and Neisseria having still high molecular weight protein (95 KDa). Bacterial strains isolated from coir-ret-liquor showed tolerance to high phenol concentration.