DEGRADATION OF COMPLEX CARBON SOURCES BY TWO STRAINS OF Thermoanaerobacterium thermosaccharolyticum.

DIAZ PEÑA ROCIO; MÉNDEZ BEATRIZ; DIEGO EGOBURO; KOLENDER, A.; M. JULIA PETTINARI

San Luis

Congreso; XIII Congreso de Microbiologia General; 2018

SAMIGE

Climate change is a threat to several life forms of our planet. This effect is partially due to thepreferential use of fossil fuels to sustain human activities such as house heating, agriculture ortransportation. The use of biofuels is one of the most promising alternatives, as it would help reducethe effects of climate change, while avoiding the use of non-renewable sources such as petroleum orgas as sources of energy. Among the most common biofuels are alcohols that can be obtained frommicrobial fermentation using different kinds of carbon sources. Many different processes have beendeveloped to obtain alcohols from sugars or starch, but the use of these substrates to produce biofuelswould compete with food supplies. To avoid this problem, biofuels should be obtained from non-foodsubstrates, such as lignocellulosic biomass.Several different approaches have been employed to use this substrate, most of which start with thehydrolysis of the biomass to obtain sugars that can be fermented. Although large amounts of energyare required for the hydrolysis steps, and only a fraction of the hydrolysis products can be converted.The use of microorganisms that have the capability to degrade lignocellulosic biomass and synthesizebiofuels would help to reduce or eliminate the lignocellulose hydrolysis steps, thereby increasing thesustainability of the processes.In this work we analyzed differences in the use of xylan and lignocellulosic biomass (sugarcaneagricultural residue) by two strains of Thermoanaerobacterium thermosaccharolyticum. T.thermosaccharolyticum GSU5 isolated in our laboratory and the collection strain T.thermosaccharolyticum DSM 571. These strains are anaerobic thermophilic solventogenic bacteriathat can produce butanol and ethanol from these substrates.Using High Resolution Liquid Chromatograph (HPLC) we observed that both strains were able todegrade corn xylan and sugarcane agricultural residue evidenced by the decrease in the area of peakscorresponding to high molecular weight hydrates and the increase in low molecular weight peaks.Furthermore, using Nuclear Magnetic Resonance (NMR), we observed differences in the degradationof the substrates between the two strains. We were able to determine the composition of Corn xylan byacid hydrolysis and acetylation followed by Gas Chromatography (GC). Analysis of the remainingsubstrate after bacterial growth allowed us to determine the main type of sugar used.Congreso Argentino de Microbiología General SAMIGE - 2018In conclusion, we could demonstrate that the two strains of T. thermosaccharolyticum are able to growon complex substrates such as xylan and lignocellulosic biomass, and we determined the way eachstrain processes these substrates. These results are interesting for the development of biofuels, andespecially relevant for our country, because sugarcane biomass is an economic substrate that isgenerated as a contaminating residue during sugarcane harvest.Congreso