title: Direct fermentation of xylan by Clostridium strain BOH3 for the production of butanol and hydrogen using optimized culture medium.
abstract: Clostridium strain BOH3 is able to utilize 10 g/l of xylan in reinforced clostridial medium (RCM) and produce butanol and hydrogen. However, increasing xylan concentration to 30 g/l does not enhance the production of butanol and hydrogen due to insufficient expression of xylanase enzyme (27.5 U/mg). To enhance the xylanase activity, an optimized culture medium (OCM), which consists of sugarcane bagasse hydrolysate (11.75 g/l), ammonium sulfate (8.92 g/l) and iron (III) chloride (1.45 mM) is designed. In the optimized OCM, Clostridium strain BOH3 expresses more xylanase and shows higher xylanase activity (44.05 ± 0.25 U/mg) in the OCM. This activity is about 1.6-fold higher than that in the original RCM. Employing OCM as a medium, Clostridium strain BOH3 effectively ferments high concentration (30 and 50 g/l) of xylan and produces 12.05 ± 0.15 and 14.80 ± 0.15 g/l of butanol and 1.78 ± 0.08 and 2.65 ± 0.15 l/l of hydrogen, respectively.
authors.affiliation: Department of Chemical and Biomolecular Engineering, 4 Engineering Drive 4, Block E5-02-09, National University of Singapore, Singapore 117576, Singapore.
authors.forename: Gobinath
authors.initials: G
authors.lastname: Rajagopalan
authors.affiliation: Department of Civil and Environmental Engineering, 1 Engineering Drive 2, Block E1A-07-03 National University of Singapore, Singapore 117576, Singapore.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Chemical and Biomolecular Engineering, 4 Engineering Drive 4, Block E5-02-09, National University of Singapore, Singapore 117576, Singapore. Electronic address: cheyk@nus.edu.sg.
authors.forename: Kun Lin
authors.initials: KL
authors.lastname: Yang
mesh_terms: D020001:1-Butanol / Q000378:metabolism*; D000704:Analysis of Variance; D003013:Clostridium / Q000187:drug effects / Q000378:metabolism*; D003470:Culture Media / Q000494:pharmacology*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism; D005285:Fermentation; D006859:Hydrogen / Q000378:metabolism*; D012044:Regression Analysis; D014990:Xylans / Q000378:metabolism*; D014994:Xylose / Q000378:metabolism
chemical_list: D003470:Culture Media; D014990:Xylans; D006859:Hydrogen; D020001:1-Butanol; D014994:Xylose; D043364:Endo-1,4-beta Xylanases
keywords: ABE fermentation; Biohydrogen; Clostridium spp.; Response surface methodology; Xylanase