The sequential microbial breakdown of pectin is the principal incident during water retting of jute (Corchorus spp.) bast fibres.

The extraction of bast fibres such as jute from plant stems involves the removal of pectin, hemicellulose, and other noncellulosic materials through a complex microbial community. A consortium of pectinolytic bacterial strains has been developed and commercialized to reduce the retting time and enhance fibre quality. However, there are currently no studies on jute that describe the structural changes and sequential microbial colonization and pectin loss that occur during microbe-assisted water retting. This study investigated the stages of microbial colonization, microbial interactions, and sequential degradation of pectic substances from jute bark under controlled and conventional water retting. The primary occurrence during water retting of bast fibres is the bacterially induced sequential breakdown of pectin surrounding the fibre bundles. The study also revealed that the pectin content of the jute stem significantly decreases during the retting process. These findings provide a strong foundation for improving microbial strains for improved pectinolysis with immense industrial significance, leading to a sustainable jute-based "green" economy.

Microbial biosurfactants: Multifarious applications in sustainable agriculture.

Agriculture in the 21st century faces grave challenges to meet the unprecedented food demand of the burgeoning population as well as reduce the ecological footprint for achieving sustainable development goals. The extensive use of harsh synthetic surfactants in pesticides and the agrochemical industry has substantial adverse impacts on the soil and environment due to their toxic and non-biodegradable nature. Biosurfactants derived from plant, animal, and microbial sources can be an eco-friendly alternative to chemical surfactants. Microbes producing biosurfactants play a noteworthy role in biofilm formation, plant pathogen elimination, biodegradation, bioremediation, improving nutrient bioavailability, and can thrive well under stressful environments. Microbial biosurfactants are well suited for heavy metal and organic contaminants remediation in agricultural soil due to their low toxicity, high activity at fluctuating temperatures, biodegradability, and stability over a wide array of environmental conditions. This green technology will improve the agricultural soil quality by increasing the soil flushing efficiency, mobilization, and solubilization of nutrients by forming metal-biosurfactant complexes, and through the dissemination of complex nutrients. Such characteristics help it to play a pivotal role in environmental sustainability in the foreseeable future, which is required to increase the viability of biosurfactants for extensive commercial uses, making them accessible, affordable, and economically sustainable.

Optimization of alkali pretreatment and enzymatic saccharification of jute (Corchorus olitorius L.) biomass using response surface methodology.

Reduction of inherent structural recalcitrance and improved saccharification efficiency are two important facets to enhance fermentable sugar yield for bioethanol production from lignocellulosic biomass. This study optimized alkaline pretreatment and saccharification conditions employing response surface methodology to improve saccharification yield of jute (Corchorus olitorius cv. JROB-2) biomass. The biomass is composed of cellulose (66.6 %), lignin (19.4 %) and hemicellulose (13.1 %). NaOH concentration exhibited significant effect on delignification during pretreatment. The highest delignification (80.42 %) was obtained by pretreatment with 2.47 % NaOH at 55.8 °C for 5.9 h removing 79.8 % lignin and 34.2 % hemicellulose from biomass, thereby increasing cell wall porosity and allowing better accessibility to saccharification enzyme. During saccharification optimization, significant effect was observed for biomass loading, enzyme concentration and temperature. Optimized saccharification condition yielded maximum saccharification (76.48 %) when hydrolysis was performed at 6.9 % biomass loading with enzyme concentration of 49.52 FPU/g substrate at 51.05 °C for 74.46 h.

Genome Comparison Identifies Different Bacillus Species in a Bast Fibre-Retting Bacterial Consortium and Provides Insights into Pectin Degrading Genes.

Retting of bast fibres requires removal of pectin, hemicellulose and other non-cellulosic materials from plant stem tissues by a complex microbial community. A microbial retting consortium with high-efficiency pectinolytic bacterial strains is effective in reducing retting-time and enhancing fibre quality. We report comprehensive genomic analyses of three bacterial strains (PJRB 1, 2 and 3) of the consortium and resolve their taxonomic status, genomic features, variations, and pan-genome dynamics. The genome sizes of the strains are ~3.8 Mb with 3729 to 4002 protein-coding genes. Detailed annotations of the protein-coding genes revealed different carbohydrate-degrading CAZy classes viz. PL1, PL9, GH28, CE8, and CE12. Phylogeny and structural features of pectate lyase proteins of PJRB strains divulge their functional uniqueness and evolutionary convergence with closely related Bacillus strains. Genome-wide prediction of genomic variations revealed 12461 to 67381 SNPs, and notably many unique SNPs were localized within the important pectin metabolism genes. The variations in the pectate lyase genes possibly contribute to their specialized pectinolytic function during the retting process. These findings encompass a strong foundation for fundamental and evolutionary studies on this unique microbial degradation of decaying plant material with immense industrial significance. These have preponderant implications in plant biomass research and food industry, and also posit application in the reclamation of water pollution from plant materials.

Optimization of the Cellulase Free Xylanase Production by Immobilized Bacillus Pumilus.

BACKGROUND: The extracellular xylanase secreted by microorganisms is a hydrolytic enzyme, which arbitrarily cleaves the ß-1, 4 backbone of the polysaccharide xylan; an enzyme used in the food processing, bio-pulping and bio-bleaching. The commercial production of the xylanase is limited because of a higher cost involvement, which can be overcome by the cost-effective production of the xylanase through immobilization of the microbial cell by the non-toxic substances. OBJECTIVES: In this work, the optimization of the extra-cellular cellulase free xylanase production by the immobilized cell of the Bacillus pumilus IMAU80221 strain using Ca-alginate beads along with standardization of the various parameters for a higher xylanase production were studied. MATERIALS AND METHODS: Following to sterilization, the Na-alginate solution was mixed with the bacterial suspension of the Bacillus pumilus IMAU80221 and was added drop by drop into the 1 M calcium chloride solution for 1 h for obtaining a uniform sized polymeric bead of the Ca-alginate. For xylanase production, the Ca-alginate beads were then transferred into 100 mL Erlenmeyer flasks with 20 mL of the culture medium containing (w/v) 0.02% NaCl, 0.02% MgSO4, 0.04% (KH4)2PO4, 0.1% peptone, and 0.5% xylan and incubated at 34 °C in an incubator shaker (150 rpm) for 24 h. The resultant supernatant (crude enzyme) was used for enzyme assay. RESULTS: The maximum xylanase production by the free cell (1.9 U.mL-1.min-1) was recorded at 48 h which was 40.5% lower than the xylanase production by the immobilized cell (2.67 U.mL-1.min-1) at the same time. The beads containing the immobilized cells could be reused up to eight fermentation cycles for xylanase production and retained 83.5% of the productivity at the fourth cycle. The entrapped cells were stable after six months of storage at 4 °C and retained 68% of the xylanase productivity. CONCLUSION: Cellulase free xylanase production from the immobilized Bacillus pumilus IMAU80221 was optimized. The xylanase production by the immobilized cells of Bacillus pumilus was higher by 40.5 and 132.6 % over the free cells respectively after 48 and 72 h of the incubation.