Isolation and characterisation of anaerobic cellulose-degrading bacteria from East African porcupine (Hystrix cristata)

Two strains of obligately anaerobic cellulolytic bacteria designated as PS7 and PS8 (PS for porcupine species) were isolated from hindgut fluid of a c rested porcupine (Hystrix cristata). The rates of cellulose degradation, to tal volatile fatty acids, and gas production from cellulose by the isolates were determined in comparison with Ruminococcus pavefaciens FD-1. xuminoco ccus pavefaciens FD-I degraded acid swollen cellulose and produced total vo latile fatty acid at a faster rate (0.03145 mg/d; 3.8350 mu mol/mL) than PS 7 (0.03113 mg/d; 2.5278 mu mol/mL) and PS8 (0.0125 mg/d; 2.1080 mu m/mL). H owever, PS7 degraded cellulose strips (untreated) faster (1.5 weeks) than R . flavefaciens FD-I (2 weeks). Furthermore, PS7 produced gas at a higher ra te (0.1055 ml/d) than R. flavefaciens FD-1 (0.03245 ml/d) more produced but yric, isovaleric acids and almost twice the amounts of total volatile fatty acids from acid swollen cellulose. Both PS7 and PS8 were Gram variable, ro d shaped and motile. On cellobiose medium, PS7 grew at temperature ranges f rom 25 to 45 degrees C while PS8 did not grow at 25 and 45 degrees C. Both isolates grew at pH levels between 6.2 and Il. Characterisation based on ca rbohydrate fermentation and morphology indicated that these two isolates we re similar. Characterisation by RAPD-PCR suggested that PS7 and PS8 were ge notypically similar but distinct. Phylogenetic analysis using the nucleotid e sequence (1450 bp) of the 16S rRNA gene suggested that PS7 clustered with Clostridium sub-phylum and exhibited the highest similarity (95%) with Clo stridium lentocellum. The phylogenetic results suggest that PS7 might repre sent a new taxon. (C) 1999 Academic Press.