Isolation and Screening of Fungal Culture Isolated From Algerian Soil for the Production of Cellulase and Xylanase

Lignocellulolytic enzymes constitute a very large group of extracellular proteins secreting by fungi who is ecologically involved in the degradation of a variety of complex materials, a property that is attributed to a battery of enzymes produced by these microorganisms like cellulases and xylanases who are of significant industrial value and relevance. Forty fungal isolated from rich soil in organic matter were screened for lignocellulolytic enzymes production, its organized on the basis of their hydrolytic potential of cellulose and xylan. The isolates strains presented enzymatic activity which was ranked as follows: cellulolytic (56%), xylanolytic (44%). Some selected strains that produce high levels of enzymes (cellulase, xylanase) grown in submerged fermentation (SmF) and were quantitatively evaluated. The fermentation experiments were carried out in shake flasks. The highest CMCase (5,10 IU/ml) and xylanase (98,25 IU/ml) activities were obtained from Trichoderma sp strain Mtr6 isolate. Keywords: Fungi, Trichoderma sp, lignocellulolytic enzymes, soil, screening, organic matter.

High-Quality Draft Genome Sequences of Marine Fish Gut Bacillus sp. Strains ABP1 and ABP2 with Nonstarch Polysaccharide Hydrolytic Potential

Here, we present the genome sequences of two environmental Bacillus strains with broad hydrolytic capacity toward different nonstarch polysaccharides (NSPs) that were isolated from the gut of marine fish fed NSP-rich diets. Several genes that may contribute to the NSP-degrading behavior were identified through in silico analysis.

Carbohydrate Hydrolytic Potential and Redundancy of an Anaerobic Digestion Microbiome Exposed to Acidosis, as Uncovered by Metagenomics

ABSTRACTIncreased hydrolysis of easily digestible biomass may lead to acidosis of anaerobic reactors and decreased methane production. Previously, it was shown that the structure of microbial communities changed during acidosis; however, once the conditions are back to optimal, biogas (initially CO2) production quickly restarts. This suggests the retention of the community functional redundancy during the process failure. In this study, with the use of metagenomics and downstream bioinformatics analyses, we characterize the carbohydrate hydrolytic potential of the microbial community, with a special focus on acidosis. To that purpose, carbohydrate-active enzymes were identified, and to further link the community hydrolytic potential with key microbes, bacterial genomes were reconstructed. In addition, we characterized biochemically the specificity and activity of selected enzymes, thus verifying the accuracy of thein silicopredictions. The results confirm the retention of the community hydrolytic potential during acidosis and indicateBacteroidetesto be largely involved in biomass degradation.Bacteroidetesshowed higher diversity and genomic content of carbohydrate hydrolytic enzymes that might favor the dominance of this phylum over other bacteria in some anaerobic reactors. The combination of bioinformatic analyses and activity tests enabled us to propose a model of acetylated glucomannan degradation byBacteroidetes.IMPORTANCEThe enzymatic hydrolysis of lignocellulosic biomass is mainly driven by the action of carbohydrate-active enzymes. By characterizing the gene profiles at the different stages of the anaerobic digestion experiment, we showed that the microbiome retains its hydrolytic functional redundancy even during severe acidosis, despite significant changes in taxonomic composition. By analyzing reconstructed bacterial genomes, we demonstrate thatBacteroideteshydrolytic gene diversity likely favors the abundance of this phylum in some anaerobic digestion systems. Further, we observe genetic redundancy within theBacteroidetesgroup, which accounts for the preserved hydrolytic potential during acidosis. This work also uncovers new polysaccharide utilization loci involved in the deconstruction of various biomasses and proposes the model of acetylated glucomannan degradation byBacteroidetes. Acetylated glucomannan-enriched biomass is a common substrate for many industries, including pulp and paper production. Using naturally evolved cocktails of enzymes for biomass pretreatment could be an interesting alternative to the commonly used chemical pretreatments.