Optimisation of xylanases production by two Cellulomonas strains and their use for biomass deconstruction

Abstract

One of the main distinguishing features of bacteria belonging to the Cellulomonas genus is their ability to secrete multiple polysaccharide degrading enzymes. However, their application in biomass deconstruction still constitutes a challenge. We addressed the optimisation of the xylanolytic activities in extracellular enzymatic extracts of Cellulomonas sp. B6 and Cellulomonas fimi B-402 for their subsequent application in lignocellulosic biomass hydrolysis by culture in several substrates. As demonstrated by secretomic profiling, wheat bran and waste paper resulted to be suitable inducers for the secretion of xylanases of Cellulomonas sp. B6 and C. fimi B-402, respectively. Both strains showed high xylanolytic activity in culture supernatant although Cellulomonas sp. B6 was the most efficient xylanolytic strain. Upscaling from flasks to fermentation in a bench scale bioreactor resulted in equivalent production of extracellular xylanolytic enzymatic extracts and freeze drying was a successful method for concentration and conservation of the extracellular enzymes, retaining 80% activity. Moreover, enzymatic cocktails composed of combined extra and intracellular extracts effectively hydrolysed the hemicellulose fraction of extruded barley straw into xylose and xylooligosaccharides. Key points • Secreted xylanase activity of Cellulomonas sp. B6 and C. fimi was maximised. • Biomass-induced extracellular enzymes were identified by proteomic profiling. • Combinations of extra and intracellular extracts were used for barley straw hydrolysis.

Important soil microbiota's effects on plants and soils: a comprehensive 30-year systematic literature review

“…For example, different proteases and polysaccharide hydrolases can be released by Bacillus subtilis and Bacillus licheniformis (Bais et al, 2004 ; Lee et al, 2022 ). Cellulomonas uda is a wet cellulose bacterium belonging to the Cellulomonas genus that can break down complex macromolecular organic materials into simpler compounds (Pérez-Avalos et al, 2008 ; Ontañon et al, 2021 ). Bacteria are also frequently employed to break down organic contaminants in soil.…”

Is beef quality affected by the inclusion of distiller grains in cattle diets?

“…Proteins of interest from SDS‐PAGE were carefully excised by hand, placed in clean Eppendorf tubes, and sent for their analysis to the Proteomics Core Facility CEQUIBIEM, at the University of Buenos Aires/National Research Council, Argentina. Protein digestion and mass spectrometry were performed as Ontañon et al (2021). Briefly, protein bands of interest were excised from Coomassie‐stained SDS‐PAGE gel and digested with trypsin.…”

Valorization of lignocellulosic wastes for sustainable xylanase production from locally isolated Bacillus subtilis exploited for xylooligosaccharides’ production with potential antimicrobial activity

“…From the environmental perspective, the application of enzymes for lignocellulose hydrolysis gained much attention as an eco-friendly and cost-effective alternative for biomass conversion (Sunkar et al 2020 ). Xylan represents 20–30% of hemicellulose, and hence, xylanases were widely reported as a promising tool for efficient agricultural wastes valorization to value-added products (Sunkar et al 2020 ; Ontañon et al 2021 ). Xylanases catalyze the hydrolyze β-1,4 glycosidic linkages in xylan to release β-d-xylopyranosyl mono-, di-, and trisaccharides (Malhotra and Chapadgaonkar 2018 ).…”