title: Minimization of diauxic growth lag-phase for high-efficiency biogas production.
abstract: The objective of this study was to develop a minimization method of a diauxic growth lag-phase for the biogas production from agricultural by-products (ABPs). Specifically, the effects of proximate composition on the biogas production and degradation rates of the ABPs were investigated, and a new method based on proximate composition combinations was developed to minimize the diauxic growth lag-phase. Experiments were performed using biogas potential tests at a substrate loading of 2.5 g VS/L and feed to microorganism ratio (F/M) of 0.5 under the mesophilic condition. The ABPs were classified based on proximate composition (carbohydrate, protein, and fat etc.). The biogas production patterns, lag phase, and times taken for 90% biogas production (T90) were used for the evaluation of the biogas production with biochemical methane potential (BMP) test. The high- or medium-carbohydrate and low-fat ABPs (cheese whey, cabbage, and skim milk) showed a single step digestion process and low-carbohydrate and high-fat ABPs (bean curd and perilla seed) showed a two-step digestion process. The mixture of high-fat ABPs and high-carbohydrate ABPs reduced the lag-phase and increased the biogas yield more than that from single ABP by 35-46%.
authors.affiliation: Department of Biosystems Engineering, College of Agriculture and Life Sciences, Kangwon National University, Hyoja 2 Dong, 192-1, Chuncheon 200-701, Republic of Korea.
authors.forename: Min Jee
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Biosystems Engineering, College of Agriculture and Life Sciences, Kangwon National University, Hyoja 2 Dong, 192-1, Chuncheon 200-701, Republic of Korea. Electronic address: shkim@kangwon.ac.kr.
authors.forename: Sang Hun
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000383:Agriculture; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D056804:Biofuels; D019149:Bioreactors; D001937:Brassica; D002611:Cheese; D006801:Humans; D008697:Methane / Q000096:biosynthesis*; D013997:Time Factors
chemical_list: D056804:Biofuels; D008697:Methane
keywords: Agricultural by-products; Anaerobic digestion; Biogas production; Diauxic growth; Lag-phase