Characterization of a novel Clostridium sp. SP17-B1 and its application for succinic acid production from hevea wood waste hydrolysate

摘要

An anaerobic, gram-positive, rod-shaped bacterium strain SP17-B1, isolated from dog saliva, was taxonomically characterized on the basis of phenotypic, chemotaxonomic, and genotypic characteristics. It was cultured in 4% (w/v) NaCl at a pH range of 5.0-8.0 (optimally at pH 7) and at 30 degrees C-40 degrees C (optimally at 37 degrees C). Its major cellular fatty acids are C-16:0 (36.3%), C-17:0 cyclo (9.7%), C-16:1 omega 9c (13.9%), and C-18:1 omega 9c (10.7%), and its DNA guanine-cytosine content is 40.8 mol%. On the basis of the 16S rRNA gene sequence analysis, it was determined that the strain belonged to the genus Clostridium and was closely related to C. amygdalinum BR-10(T) (97.8%), C. saccharolyticum WM1(T) (97.8%), and C. celleracrescens DSM 5628(T) (97.7%). This strain showed a low level of DNA-DNA relatedness with the closely related strains, suggesting that it is a novel species in the genus Clostridium. Recent studies have demonstrated the production of succinic acid using Clostridium strains. Strain SP17-B1 produced 25.1 +/- 1.3 and 15.3 +/- 1.5 g/L of succinic acid from 40 g/L of glucose and 30 g/L of hevea wood waste hydrolysate (HH), respectively, after 24 h. When detoxified HH was used as a substrate, the lag phase was reduced and cell growth was enhanced by 7 fold (OD660 0.4-3.0) within 12 h. Detoxification using granular activated carbon may have reduced the levels of furfural and HMF without interfering with the amount of sugars in HH. (C) 2019 Elsevier Ltd. All rights reserved.