title: Alkaline direct transesterification of different species of Stichococcus for bio-oil production.
abstract: The cost of bio-oil refining from microalgal biomass can be significantly reduced by combining extraction and transesterification. The characterisation and optimisation of the combined steps have been carried out on strains of Stichococcus bacillaris, focusing on catalyst type and concentration, reaction time and temperature, methanol/biomass ratio, pre-mixing time and water content in the biomass. The bio-oil yield has been referenced as production of fatty acid methyl esters (FAMEs). The maximum yield (∼17%) was achieved using dried biomass with alkaline catalyst at 60°C and methanol/biomass weight ratio of 79:1. Alkaline catalyst conditions gave faster reaction rates and higher bio-oil yields than acid catalyst. Yield was also strongly affected by water content in the biomass. A mechanistic interpretation has been proposed to elucidate the effect of the different operating conditions. However, the structural characteristics of the Chlorophyta cell wall can be very different, leading to different bio-oil yields when the same protocol is applied. Therefore, the optimised protocol of direct transesterification for Stichococcus bacillaris strains was tested on other Stichococcus strains and several other Chlorophyta species characterised by a different cell wall structure. It was clearly demonstrated that different results for bio-oil yield were obtained within the same microalgal species and much more within different microalgal genera.
authors.affiliation: Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli "Federico II", P.le V. Tecchio, 80-80125 Napoli, Italy. Electronic address: immacolata.gargano@unina.it.
authors.forename: Immacolata
authors.initials: I
authors.lastname: Gargano
authors.affiliation: Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli "Federico II", P.le V. Tecchio, 80-80125 Napoli, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Marotta
authors.affiliation: Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli "Federico II", P.le V. Tecchio, 80-80125 Napoli, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Andreozzi
authors.affiliation: Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli "Federico II", P.le V. Tecchio, 80-80125 Napoli, Italy; Bioprocess Engineering, Wageningen University, P.O. Box 16, 6700 AA, Wageningen, Netherlands.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Olivieri
authors.affiliation: Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli "Federico II", P.le V. Tecchio, 80-80125 Napoli, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Marzocchella
authors.affiliation: Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli "Federico II", P.le V. Tecchio, 80-80125 Napoli, Italy; Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica, Politecnico di Bari, Via E. Orabona, 4-70125, Bari, Italy.
authors.forename: Danilo
authors.initials: D
authors.lastname: Spasiano
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Napoli "Federico II", Complesso Universitario di Monte Sant' Angelo, Via Cintia, 26-80126 Napoli, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Pinto
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Napoli "Federico II", Complesso Universitario di Monte Sant' Angelo, Via Cintia, 26-80126 Napoli, Italy.
authors.forename: Antonino
authors.initials: A
authors.lastname: Pollio
mesh_terms: D055162:Biocatalysis; D056804:Biofuels; D018533:Biomass; D001709:Biotechnology; D002473:Cell Wall / Q000378:metabolism; D000460:Chlorophyta / Q000145:classification / Q000254:growth & development / Q000378:metabolism*; D004951:Esterification; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D000432:Methanol / Q000378:metabolism; D058086:Microalgae / Q000145:classification / Q000254:growth & development / Q000378:metabolism; D013045:Species Specificity
chemical_list: D056804:Biofuels; D000432:Methanol
keywords: Bio-oil; Biorefinery; Microalgae; Stichococcus; Transesterification