Dilution-to-stimulation/extinction : a "top-down" strategy to develop a minimal, effective and versatile lignocellulolytic microbial consortium

The enzymes secreted by lignocellulolytic microbial consortia could potentially boost saccharification processes in biorefineries. Here, we developed a minimal and effective lignocellulolytic microbial consortium (MELMC) using a sequential combination of dilution-to-stimulation and dilution-to-extinction approaches. The consortium was retrieved from Andean forest soil and selected through incubation in liquid media with a mixture of three types of agricultural plant residues. After the dilution-to-stimulation phase, approximately 50 bacterial sequence types, mostly belonging to the Sphingobacteriaceae, Enterobacteriaceae, Pseudomonadaceae and Paenibacillaceae, were significantly enriched. At this stage, fungal populations were low abundant. The dilution-to-extinction method demonstrated that only eight of the bacterial sequence types were necessary to maintain microbial growth and plant biomass degradation percentages at high levels (i.e. ~5.5%). After a subsequent stabilization, only two bacterial species (Pseudomonas sp. and Paenibacillus sp.) became highly abundant (> 99%) within the MELMC, indicating that these are the key players of degradation. Differences in the composition of bacterial communities between biological replicates indicated that selection, sampling and/or priority effects could shape the consortium structure. The MELMC can degrade up to ~13% of corn stover, consuming mostly its (hemi)cellulosic fraction. Tests with chromogenic substrates showed that the MELMC secrete an array of enzymes able to degrade xylan, arabinoxylan, carboxymethyl cellulose and wheat straw. Additionally, a predictive metagenomic profile demonstrated that the MELMC has the potential to produce endoglucanases, betaglucosidases, beta/alpha-galactosidases and alpha-mannosidases, suggesting a high versatility of plant biomass degradation capabilities

• Autores: Díaz García, Laura Andrea
• Fecha de publicación: 2020
• Institución: Universidad de los Andes
• Repositorio: Séneca: repositorio Uniandes
• Idioma: eng
• OAI Identifier: oai:repositorio.uniandes.edu.co:1992/48552
• Acceso en línea: http://hdl.handle.net/1992/48552
• Palabra clave: Conversión de biomasa; Lignocelulosa; Biotecnología microbiana; Suelos forestales; Biología
• Rights: openAccess
• License: http://creativecommons.org/licenses/by-nc-sa/4.0/