Identification of novel enzymes to enhance the ruminal digestion of barley straw. (July 2018)

• Record Type: Journal Article
• Authors: Badhan, Ajay; Ribeiro, Gabriel O.; Jones, Darryl R.; Wang, Yuxi; Abbott, D. Wade; Di Falco, Marcos; Tsang, Adrian; McAllister, Tim A.
• Is Part Of: Bioresource technology. Volume 260(2018)
• Page Start: 76
• Page End: 84
• Publication Date: 2018-07
• Subjects: Carbohydrate active enzymes (CAZymes) -- Rumen nutrition -- Fiber utilization -- Blue Native PAGE -- LC-MS/MS -- Glycosyl hydrolase; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2018.03.086
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Graphical representation of experimental work flow adopted to identify enzyme activities with potential to enhance ruminal digestion of barley straw. Different stages of experimental work flow i.e., screening, enzyme discovery and selection of candidate enzymes for future formulations are shown in Red, yellow and green boxes respectively. Highlights: Microassay enabled rapid screening of candidate enzymes. In-vitro rumen microbial batch cultures validated microassay results. BN PAGE fractionation/microassay isolated enzymes linked to enhanced fermentation. Mass spectrometric analysis identified enzymes linked to enhanced fermentation. Phylogenetic analysis identified candidate enzymes with high additive potential. Abstract: Crude enzyme extracts typically contain a broad spectrum of enzyme activities, most of which are redundant to those naturally produced by the rumen microbiome. Identification of enzyme activities that are synergistic to those produced by the rumen microbiome could enable formulation of enzyme cocktails that improve fiber digestion in ruminants. Compared to untreated barley straw, Viscozyme® increased gas production, dry matter digestion (P < 0.01) and volatile fatty acid production (P < 0.001) in ruminal batch cultures. Fractionation of Viscozyme® by Blue Native PAGE and analyses using a microassay and mass-spectrometry revealed a GH74 endoglucanase, GH71 α-1, 3-glucanase, GH5 mannanase, GH7 cellobiohydrolase, GH28 pectinase, and esterases from Viscozyme® contributed to enhanced saccharification of barley straw by rumen mix enzymes. Grouping of these identified activities with their carbohydrate active enzymes (CAZy) counterparts enabled selection of similar CAZymes for downstream production and screening. Mining of these specific activities from other biological systems could lead to high value enzyme formulations for ruminants.