title: Application of a novel enzymatic pretreatment using crude hydrolytic extracellular enzyme solution to microalgal biomass for dark fermentative hydrogen production.
abstract: In this study, a novel enzymatic pretreatment of Chlorella vulgaris for dark fermentative hydrogen production (DFHP) was performed using crude hydrolytic extracellular enzyme solution (CHEES) extracted from the H2 fermented effluent of food waste. It was found that the enzyme extracted at 52 h had the highest hydrolysis efficiency of microalgal biomass, resulting in the highest H2 yield of 43.1 mL H2/g dry cell weight along with shorter lag periods. Even though a high amount of VFAs was accumulated in CHEES, especially butyrate, the fermentative bacteria on the DFHP was not affected from product inhibition. It also appears that the presence of organic acids, especially lactate and acetate, contained in the CHEES facilitated enhancement of H2 production acted as a co-substrate. Therefore, all of the experimental results suggest that the enhancement of DFHP performance caused by CHEES has a dual role as the hydrolysis enhancer and the co-substrate supplier.
authors.affiliation: Department of Civil and Environmental Engineering, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Yeo-Myeong
authors.initials: YM
authors.lastname: Yun
authors.affiliation: Waste Energy Research Center, Korea Institute of Energy Research, 102 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea.
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Bioenergy Center, Korea Institute of Energy Research, 102 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea.
authors.forename: You-Kwan
authors.initials: YK
authors.lastname: Oh
authors.affiliation: Department of Civil and Environmental Engineering, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Hang-Sik
authors.initials: HS
authors.lastname: Shin
authors.affiliation: Center for Water Resources Cycle Research, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650, Republic of Korea. Electronic address: kw512@kist.re.kr.
authors.forename: Kyung-Won
authors.initials: KW
authors.lastname: Jung
mesh_terms: D061249:Batch Cell Culture Techniques; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology / Q000379:methods*; D048408:Chlorella vulgaris / Q000378:metabolism / Q000648:ultrastructure; D004275:DNA, Ribosomal / Q000235:genetics; D003624:Darkness; D058645:Denaturing Gradient Gel Electrophoresis; D005110:Extracellular Space / Q000201:enzymology*; D005285:Fermentation; D005502:Food; D006859:Hydrogen / Q000378:metabolism*; D006868:Hydrolysis; D008697:Methane / Q000096:biosynthesis; D058086:Microalgae / Q000378:metabolism* / Q000648:ultrastructure; D012996:Solutions; D014865:Waste Disposal, Fluid; D014866:Waste Products
chemical_list: D004275:DNA, Ribosomal; D012996:Solutions; D014866:Waste Products; D006859:Hydrogen; D008697:Methane
keywords: Chlorella vulgaris; Co-substrate; Crude hydrolytic extracellular enzyme solution; Food waste