title: Biodiesel production from wet microalgae feedstock using sequential wet extraction/transesterification and direct transesterification processes.
abstract: Although producing biodiesel from microalgae seems promising, there is still a lack of technology for the quick and cost-effective conversion of biodiesel from wet microalgae. This study was aimed to develop a novel microalgal biodiesel producing method, consisting of an open system of microwave disruption, partial dewatering (via combination of methanol treatment and low-speed centrifugation), oil extraction, and transesterification without the pre-removal of the co-solvent, using Chlamydomonas sp. JSC4 with 68.7 wt% water content as the feedstock. Direct transesterification with the disrupted wet microalgae was also conducted. The biomass content of the wet microalgae increased to 56.6 and 60.5 wt%, respectively, after microwave disruption and partial dewatering. About 96.2% oil recovery was achieved under the conditions of: extraction temperature, 45°C; hexane/methanol ratio, 3:1; extraction time, 80 min. Transesterification of the extracted oil reached 97.2% conversion within 15 min at 45°C and 6:1 solvent/methanol ratio with simultaneous Chlorophyll removal during the process. Nearly 100% biodiesel conversion was also obtained while conducting direct transesterification of the disrupted oil-bearing microalgal biomass.
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Ching-Lung
authors.initials: CL
authors.lastname: Chen
authors.affiliation: Department of Cosmetic Science, Providence University, Taichung, Taiwan.
authors.forename: Chien-Chang
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Kao-Chia
authors.initials: KC
authors.lastname: Ho
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Ping-Xuan
authors.initials: PX
authors.lastname: Hsiao
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Meng-Shan
authors.initials: MS
authors.lastname: Wu
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan; Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan. Electronic address: changjs@mail.ncku.edu.tw.
authors.forename: Jo-Shu
authors.initials: JS
authors.lastname: Chang
mesh_terms: D056804:Biofuels; D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D002696:Chlamydomonas / Q000378:metabolism; D004951:Esterification; D058086:Microalgae / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D056804:Biofuels; D014867:Water
keywords: Biodiesel; Direct transesterification; Microwave disruption; Oil extraction; Wet microalgae