Fig. 5
Comparative fermentation profile of Clostridium sp. DBT-IOC-C19 and Clostridium thermocellum DSM 1313 on various substrates. Comparative production of fermentation end products by (a) Clostridium thermocellum DSM 1313 and (b) Clostridium sp. strain DBT-IOC-C19 on various substrates loaded at an equivalent concentration (10 g L−1) expressed as xylose and glucose equivalents. Batch fermentations were maintained at 60 °C with initial pH 7.5 for strain DBT-IOC-C19 and pH 7.0 for strain DSM 1313 for 24–96 h. Progress in fermentation was monitored by measuring decrease in pH, acetate, lactate, and ethanol concentrations. Data are presented as average with error bars (±) showing standard deviations calculated from triplicate fermentations. The metabolite concentrations at different substrates varied with a statistical significance [ANOVA Tukey’s test, ***p < 0.001, ** 0.01 > p > 0.001, and * 0.05 > p > 0.01]. The concentrations that are not significantly different from each other in treatment condition described are labeled with same lowercase letters associated with a level of significance in the figure. PT pretreated, RSB rice straw biomass