Changes in freshwater sediment microbial populations during fermentation of crude glycerol

Background: This work studied how the exposure to an unusual substrate forced a change in microbial populations during anaerobic fermentation of crude glycerol, by-product biodiesel production, with freshwater sediment used as inoculum. Results: The associations almost completely (99.9%) utilized glycerol contained 6 g L-1 within four days, releasing gases, organic acids (acetic, butyric) and alcohols (ethanol, n-butanol) under conditions. In comparison control medium without adding increased amount ethanol n-butanol production it was not significantly affected by incubation temperature (28°C or 37°C), nor time (4 8 d), but resulted reduced butyric acid. Higher volume gas produced at 37°C despite fact that overall bacterial count smaller than one measured 20°C. Main phyla inoculum were Actinobacteria, Proteobacteria Firmicutes. During fermentation, significant changes observed Firmicutes, especially Clostridium spp., began dominate, number Actinobacteria Gammaproteobacteria decreased accordingly. Concentration Archaea decreased, glycerol. These confirmed both culturing culture-independent (concentration 16S rDNA) methods. Conclusions: Crude led adaptation this substrate. Changes community result new source carbon. Normal 0 false EN-US X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi;}