Figure 2

P. taiwanensis promotes cellulose utilization by consortia. (A) Cellulase enzyme activities of HP, HL, and HLP. Fermentation was conducted with α-cellulose for 7 days at 55°C, and the cellulase enzyme activities of the consortia with and without co-cultured P. taiwanensis at an 8.5:1 biomass ratio were measured. The maximal activities are shown. FPase, filter paper activity; EG, endoglucanase; CBH, exoglucanase; BG, β-glucosidase. HLP represents the new consortium obtained by co-culturing HL and P. taiwanensis. The error bars represent the SD (n = 3). (B) Consortium performance cannot be improved by addition of β-glucosidase. β-glucosidase was added to consortium HL at final enzyme activities of 0.2 U/mL (S1), 0.8 U/mL (S2), and 1.6 U/mL (S3) at the beginning of fermentation. The control was fermentation by consortium HL without β-glucosidase addition (HL). The error bars represent the SD (n = 3). (C) PCR-DGGE analysis of HL and HLP at two stages, including the highest filter paper activity (represented as FPase) and highest ethanol titer (represented as EtOH). (D) Principal component analysis (PCA) of the PCR-DGGE data in C. PC1 and PC2 explained 68.9% and 23.3% of the total variance, respectively.