title: Optimization of direct conversion of wet algae to biodiesel under supercritical methanol conditions.
abstract: This study demonstrated a one-step process for direct liquefaction and conversion of wet algal biomass containing about 90% of water to biodiesel under supercritical methanol conditions. This one-step process enables simultaneous extraction and transesterification of wet algal biomass. The process conditions are milder than those required for pyrolysis and prevent the formation of by-products. In the proposed process, fatty acid methyl esters (FAMEs) can be produced from polar phospholipids, free fatty acids, and triglycerides. A response surface methodology (RSM) was used to analyze the influence of the three process variables, namely, the wet algae to methanol (wt./vol.) ratio, the reaction temperature, and the reaction time, on the FAMEs conversion. Algal biodiesel samples were analyzed by ATR-FTIR and GC-MS. Based on the experimental analysis and RSM study, optimal conditions for this process are reported as: wet algae to methanol (wt./vol.) ratio of around 1:9, reaction temperature and time of about 255 °C, and 25 min respectively. This single-step process can potentially be an energy efficient and economical route for algal biodiesel production.
authors.affiliation: Chemical Engineering Department, New Mexico State University, Las Cruces, NM 88003, USA.
authors.forename: Prafulla D
authors.initials: PD
authors.lastname: Patil
authors.forename: Veera Gnaneswar
authors.initials: VG
authors.lastname: Gude
authors.forename: Aravind
authors.initials: A
authors.lastname: Mannarswamy
authors.forename: Shuguang
authors.initials: S
authors.lastname: Deng
authors.forename: Peter
authors.initials: P
authors.lastname: Cooke
authors.forename: Stuart
authors.initials: S
authors.lastname: Munson-McGee
authors.forename: Isaac
authors.initials: I
authors.lastname: Rhodes
authors.forename: Pete
authors.initials: P
authors.lastname: Lammers
authors.forename: Nagamany
authors.initials: N
authors.lastname: Nirmalakhandan
mesh_terms: D056804:Biofuels; D018533:Biomass; D004951:Esterification; D005227:Fatty Acids / Q000032:analysis / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D000432:Methanol / Q000138:chemical synthesis* / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism; D014867:Water / Q000378:metabolism*
chemical_list: D056804:Biofuels; D005227:Fatty Acids; D014280:Triglycerides; D014867:Water; D000432:Methanol