Determination of the cellulase activity distribution in Clostridium thermocellum and Caldicellulosiruptor obsidiansis cultures using a fluorescent substrate

Journal Article · Sat May 30 00:00:00 EDT 2015 · Journal of Environmental Sciences

DOI:https://doi.org/10.1016/j.jes.2015.03.009· OSTI ID:1286746

Morrell-Falvey, Jennifer L. ^[1]; Elkins, James G. ^[1]; Wang, Zhi-Wu ^[2]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC), Biosciences Division
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC), Biosciences Division; The Ohio State Univ. ATI, Wooster, OH (United States)

This study took advantage of resorufin cellobioside as a fluorescent substrate to determine the distribution of cellulase activity in cellulosic biomass fermentation systems. Cellulolytic biofilms were found to express nearly four orders greater cellulase activity compared to planktonic cultures of Clostridium thermocellum and Caldicellulosiruptor obsidiansis, which can be primarily attributed to the high cell concentration and surface attachment. The formation of biofilms results in cellulases being secreted close to their substrates, which appears to be an energetically favorable stategy for insoluble substrate utilization. For the same reason, cellulases should be closely associated with the surfaces of suspended cell in soluble substrate-fed culture, which has been verified with cellobiose-fed cultures of C. thermocellum and C. obsidiansis. This study addressed the importance of cellulase activity distribution in cellulosic biomass fermentation, and provided theoretical foundation for the leading role of biofilm in cellulose degradation. System optimization and reactor designs that promote biofilmformation in cellulosic biomass hydrolysismay promise an improved cellulosic biofuel process.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1286746
• Alternate ID(s): OSTI ID: 1250569
• Journal Information: Journal of Environmental Sciences, Vol. 34, Issue C; ISSN 1001-0742
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
59 BASIC BIOLOGICAL SCIENCES