title: Perspectives on engineering strategies for improving biofuel production from microalgae--a critical review.
abstract: Although the potential for biofuel production from microalgae via photosynthesis has been intensively investigated, information on the selection of a suitable operation strategy for microalgae-based biofuel production is lacking. Many published reports describe competitive strains and optimal culture conditions for use in biofuel production; however, the major impediment to further improvements is the absence of effective engineering strategies for microalgae cultivation and biofuel production. This comprehensive review discusses recent advances in understanding the effects of major environmental stresses and the characteristics of various engineering operation strategies on the production of biofuels (mainly biodiesel and bioethanol) using microalgae. The performances of microalgae-based biofuel-producing systems under various environmental stresses (i.e., irradiance, temperature, pH, nitrogen depletion, and salinity) and cultivation strategies (i.e., fed-batch, semi-continuous, continuous, two-stage, and salinity-gradient) are compared. The reasons for variations in performance and the underlying theories of the various production strategies are also critically discussed. The aim of this review is to provide useful information to facilitate development of innovative and feasible operation technologies for effectively increasing the commercial viability of microalgae-based biofuel production.
authors.affiliation: Organization of Advanced Science and Technology, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Shih-Hsin
authors.initials: SH
authors.lastname: Ho
authors.affiliation: Organization of Advanced Science and Technology, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Ye
authors.affiliation: Organization of Advanced Science and Technology, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hasunuma
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan; Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan; Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan. Electronic address: changjs@mail.ncku.edu.tw.
authors.forename: Jo-Shu
authors.initials: JS
authors.lastname: Chang
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan; Biomass Engineering Program, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan. Electronic address: akondo@kobe-u.ac.jp.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kondo
mesh_terms: D056804:Biofuels; D001709:Biotechnology / Q000379:methods*; D060847:Metabolic Engineering / Q000379:methods*; D058086:Microalgae / Q000737:chemistry / Q000378:metabolism*
chemical_list: D056804:Biofuels
keywords: Biofuel; Continuous operation; Engineering operation strategy; Environmental stress; Fed-batch operation; Microalgae; Salinity-gradient operation; Semi-continuous operation; Two-stage operation