title: Microalgae harvesting and subsequent biodiesel conversion.
abstract: Chlorella vulgaris ESP-31 containing 22.7% lipid was harvested by coagulation (using chitosan and polyaluminium chloride (PACl) as the coagulants) and centrifugation. The harvested ESP-31 was directly employed as the oil source for biodiesel production via transesterification catalyzed by immobilized Burkholderia lipase and by a synthesized solid catalyst (SrO/SiO2). Both enzymatic and chemical transesterification were significantly inhibited in the presence of PACl, while the immobilized lipase worked well with wet chitosan-coagulated ESP-31, giving a high biodiesel conversion of 97.6% w/w oil, which is at a level comparable to that of biodiesel conversion from centrifugation-harvested microalgae (97.1% w/w oil). The immobilized lipase can be repeatedly used for three cycles without significant loss of its activity. The solid catalyst SrO/SiO2 worked well with water-removed centrifuged ESP-31 with a biodiesel conversion of 80% w/w oil, but the conversion became lower (55.7-61.4% w/w oil) when using water-removed chitosan-coagulated ESP-31 as the oil source.
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Dang-Thuan
authors.initials: DT
authors.lastname: Tran
authors.forename: Bich-Hanh
authors.initials: BH
authors.lastname: Le
authors.forename: Duu-Jong
authors.initials: DJ
authors.lastname: Lee
authors.forename: Ching-Lung
authors.initials: CL
authors.lastname: Chen
authors.forename: Hsiang-Yu
authors.initials: HY
authors.lastname: Wang
authors.forename: Jo-Shu
authors.initials: JS
authors.lastname: Chang
mesh_terms: D000536:Aluminum Hydroxide / Q000494:pharmacology; D056804:Biofuels; D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D019117:Burkholderia / Q000187:drug effects / Q000201:enzymology; D002384:Catalysis / Q000187:drug effects; D002498:Centrifugation; D048271:Chitosan / Q000494:pharmacology; D048408:Chlorella vulgaris / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D004800:Enzymes, Immobilized / Q000378:metabolism; D004951:Esterification / Q000187:drug effects; D005427:Flocculation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008049:Lipase / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D058086:Microalgae / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D010316:Particle Size; D012822:Silicon Dioxide / Q000494:pharmacology; D055672:Static Electricity; D013324:Strontium / Q000494:pharmacology; D013997:Time Factors
chemical_list: D056804:Biofuels; D004800:Enzymes, Immobilized; D008055:Lipids; C016213:aluminum oxychloride; D000536:Aluminum Hydroxide; D012822:Silicon Dioxide; D048271:Chitosan; D008049:Lipase; D013324:Strontium