BACKGROUND: Synergistic action of different enzymes is required to complete the degradation of plant biomass in order to release @entity3363 which are useful for biorefining. However, the use of single strains is often not efficient, as crucial parts of the required enzymatic machinery can be absent. The use of microbial consortia bred on plant biomass is a way to overcome this hurdle. In these, secreted proteins constitute sources of relevant enzyme cocktails. Extensive analyses of the proteins secreted by effective microbial consortia will contribute to a better understanding of the mechanism of lignocellulose degradation. RESULTS: Here, we report an analysis of the proteins secreted by a microbial consortium (metasecretome) that was grown on either @entity3505 straw ( @entity26320 ), @entity6122 or xylan as the @entity505 sources. Liquid chromatography-tandem mass spectrometry was used to analyze the proteins in the supernatants. Totals of 768 ( @entity26320 ), 477 ( @entity6122 ) and 103 (xylan) proteins were identified and taxonomically and functionally classified. In @entity26320 , the proteins were mostly affiliated with Sphingobacterium-like consortium members (~50  %). Specific abundant protein clusters were predicted to be involved in polysaccharide transport and/or sensing (TonB-dependent receptors). In addition, proteins predicted to degrade plant biomass, i.e. endo-1,4-beta-xylanases, alpha-l-arabinofuranosidases and alpha-l-fucosidases, were prominent. In the @entity6122 -driven consortium, most secreted proteins were affiliated with those from Enterobacteriales (mostly Klebsiella species), whereas in the xylan-driven one, they were related to Flavobacterium-like ones. Notably, the metasecretomes of the consortia growing on @entity6122 and xylan contained proteins involved in diverse metabolic functions (e.g. membrane proteins, isomerases, dehydrogenases and oxidoreductases). CONCLUSIONS: An analysis of the metasecretomes of microbial consortia originating from the same source consortium and subsequently bred on three different @entity505 sources indicated that the major active microorganisms in the three final consortia differed. Importantly, diverse glycosyl hydrolases, predicted to be involved in (hemi)cellulose degradation (e.g. of CAZy families GH3, GH10, GH43, GH51, GH67 and GH95), were identified in the @entity26320 metasecretome. Based on these results, we catalogued the @entity26320 consortium as a true microbial enzyme factory that constitute an excellent source for the production of an efficient enzyme cocktail for the pretreatment of plant biomass.

Metasecretome analysis of a lignocellulolytic microbial consortium grown on @entity3505 straw, xylan and XXXX .

@entity6122 :: ('MESH:D014994', 'Chemical') :: ['xylose'] @entity3363 :: ('MESH:D002241', 'Chemical') :: ['sugars'] @entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon'] @entity3505 :: ('4565', 'Species') :: ['wheat'] @entity26320 :: ('MESH:D029597', 'Disease') :: ['RWS']
@entity6122 :: (MESH:D014994,Chemical) :: ['xylose']
