title: Mild-temperature thermochemical pretreatment of green macroalgal biomass: Effects on solubilization, methanation, and microbial community structure.
abstract: The effects of mild-temperature thermochemical pretreatments with HCl or NaOH on the solubilization and biomethanation of Ulva biomass were assessed. Within the explored region (0-0.2M HCl/NaOH, 60-90°C), both methods were effective for solubilization (about 2-fold increase in the proportion of soluble organics), particularly under high-temperature and high-chemical-dose conditions. However, increased solubilization was not translated into enhanced biogas production for both methods. Response surface analysis statistically revealed that HCl or NaOH addition enhances the solubilization degree while adversely affects the methanation. The thermal-only treatment at the upper-limit temperature (90°C) was estimated to maximize the biogas production for both methods, suggesting limited potential of HCl/NaOH treatment for enhanced Ulva biomethanation. Compared to HCl, NaOH had much stronger positive and negative effects on the solubilization and methanation, respectively. Methanosaeta was likely the dominant methanogen group in all trials. Bacterial community structure varied among the trials according primarily to HCl/NaOH addition.
authors: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 689-798, Republic of Korea.
authors: Heejung
authors: H
authors: Jung
authors: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 689-798, Republic of Korea.
authors: Gahyun
authors: G
authors: Baek
authors: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 689-798, Republic of Korea.
authors: Jaai
authors: J
authors: Kim
authors: School of Environmental Science and Engineering, POSTECH, Pohang, Gyungbuk 790-784, Republic of Korea.
authors: Seung Gu
authors: SG
authors: Shin
authors: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 689-798, Republic of Korea. Electronic address: cslee@unist.ac.kr.
authors: Changsoo
authors: C
authors: Lee
mesh_terms: D056804:Biofuels; D018533:Biomass; D001709:Biotechnology / Q000379:methods; D006358:Hot Temperature; D008697:Methane / Q000096:biosynthesis; D059013:Microbial Consortia / Q000502:physiology*; D012624:Seaweed / Q000737:chemistry; D012995:Solubility; D044445:Ulva / Q000737:chemistry* / Q000378:metabolism
chemical_list: D056804:Biofuels; D008697:Methane
keywords: Anaerobic digestion; Macroalgae; Pretreatment; Response surface analysis; Ulva