ABSTRACT
Aim: To investigate the reduction of lignin content in jute (Corchorus spp. L.) with promising lignin degrading bacterial isolates.Methodology: Promising lignin degrading bacterial isolates were screened on the basis of potency index, MnP (manganese peroxidase) and LiP (lignin peroxidase) activities. Very efficient ligninolytic isolates were used for laboratory scale delignification trial and the resultant fibre was tested for lignin content, fibre strength and fineness. The efficient isolates were identified up to species level with Biolog Inc. based on the metabolic fingerprinting of the isolates. Results: Out of 95 ligninolytic bactetial isolates, twenty isolates having potency index >1.10 on the basis of Azure-B dye degradation test were selected for enzyme assays. Five promising isolates (L3, L9, L10, L26 and L30) were selected for delignification trial on the basis of high MnP (126 – 482 U l-1 min-1), and LiP (558.7 – 615.6 U l-1 min-1) activities. The isolate L9 performed best among the five isolates and could reduce lignin content from 11.33 to 8.84% i.e. a reduction of 21.97% from the control. All the five isolates were identified as Bacillus spp. Interpretation: Delignification of jute by using lignin degrading bacteria without any environmental hazard may be considered as an alternate method of chemical delignification for minimization of environmental pollution
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.