A whole biodiesel conversion process combining isolation, cultivation and in situ supercritical methanol transesterification of native microalgae.

A coupled process combining microalgae production with direct supercritical biodiesel conversion using a reduced number of operating steps is proposed in this work. Two newly isolated native microalgae strains, identified as Chlorella sp. and Nannochloris sp., were cultivated in both batch and continuous modes. Maximum productivities were achieved during continuous cultures with 318mg/lday and 256mg/lday for Chlorella sp. and Nannochloris sp., respectively. Microalgae were further characterized by determining their photosynthetic performance and nutrient removal efficiency. Biodiesel was produced by catalyst-free in situ supercritical methanol transesterification of wet unwashed algal biomass (75wt.% of moisture). Maximum biodiesel yields of 45.62wt.% and 21.79wt.% were reached for Chlorella sp. and Nannochloris sp., respectively. The analysis of polyunsaturated fatty acids of Chlorella sp. showed a decrease in their proportion when comparing conventional and supercritical transesterification processes (from 37.4% to 13.9%, respectively), thus improving the quality of the biodiesel.

[1]  V. Gude,et al.  Optimization of direct conversion of wet algae to biodiesel under supercritical methanol conditions. , 2011, Bioresource technology.

[2]  F. G. Acién,et al.  Marine microalgae selection and culture conditions optimization for biodiesel production. , 2013, Bioresource technology.

[3]  J. Takala,et al.  Scale-up potential of cultivating Chlorella zofingiensis in piggery wastewater for biodiesel production. , 2013, Bioresource technology.

[4]  Tapaswy Muppaneni,et al.  Direct conversion of wet algae to crude biodiesel under supercritical ethanol conditions , 2014 .

[5]  P. Lammers,et al.  In situ ethyl ester production from wet algal biomass under microwave-mediated supercritical ethanol conditions. , 2013, Bioresource technology.

[6]  U. Schreiber,et al.  Assessment of wavelength-dependent parameters of photosynthetic electron transport with a new type of multi-color PAM chlorophyll fluorometer , 2012, Photosynthesis Research.

[7]  J. Lee,et al.  Evaluation of FAME production from wet marine and freshwater microalgae by in situ transesterification , 2013 .

[8]  A Anandraj,et al.  PAM fluorometry as a tool to assess microalgal nutrient stress and monitor cellular neutral lipids. , 2011, Bioresource technology.

[9]  Mohammed M. Farid,et al.  Effective extraction of microalgae lipids from wet biomass for biodiesel production , 2014 .

[10]  B. Wang,et al.  Lewis acid-catalyzed in situ transesterification/esterification of microalgae in supercritical ethanol. , 2014, Bioresource technology.

[11]  W. Horwitz,et al.  Official methods of analysis of AOAC International , 2010 .

[12]  E. Díaz,et al.  Isolation of a new strain of Picochlorum sp and characterization of its potential biotechnological applications , 2011, Biotechnology progress.

[13]  Yingying Gao,et al.  Nutrient deprivation enhances lipid content in marine microalgae. , 2013, Bioresource technology.

[14]  B. Rosen,et al.  Protoplast induction in Chlorella pyrenoidosa , 1985 .

[15]  B. Naceur,et al.  Composition and dynamics of potentially toxic dinoflagellates in a shallow Mediterranean lagoon , 2012 .

[16]  Paul Chen,et al.  Local bioprospecting for high-lipid producing microalgal strains to be grown on concentrated municipal wastewater for biofuel production. , 2011, Bioresource technology.

[17]  K. J. Brown.  A method for turbidimetric measurement of bacterial growth in liquid cultures and agar plug diffusion cultures, using standard test tubes , 1980, European journal of applied microbiology and biotechnology.

[18]  F. G. Acién,et al.  Outdoor pilot-scale production of Nannochloropsis gaditana: influence of culture parameters and lipid production rates in tubular photobioreactors. , 2014, Bioresource technology.

[19]  Hui Wang,et al.  Integration process of biodiesel production from filamentous oleaginous microalgae Tribonema minus. , 2013, Bioresource technology.

[20]  E. Carpenter,et al.  Ultrastructure and Taxonomic Observations on Marine Isolates of the Genus Nannochloris (Chlorophyceae) , 1982 .

[21]  G. Kochert.  Carbohydrate determination by the phenol sulfuric acid method , 1978 .

[22]  Mohammad Hossein Morowvat,et al.  PCR amplification of 18S rRNA, single cell protein production and fatty acid evaluation of some naturally isolated microalgae , 2009 .

[23]  Teresa M. Mata,et al.  Microalgae for biodiesel production and other applications: A review , 2010 .

[24]  Ji-won Yang,et al.  Serial optimization of biomass production using microalga Nannochloris oculata and corresponding lipid biosynthesis , 2011, Bioprocess and Biosystems Engineering.

[25]  J. M. Fernández-Sevilla,et al.  Direct supercritical methanolysis of wet and dry unwashed marine microalgae (Nannochloropsis gaditana) to biodiesel , 2015 .

[26]  C. Soccol,et al.  Screening of microalgae with potential for biodiesel production and nutrient removal from treated domestic sewage , 2011 .

[27]  J. Quesada-Medina,et al.  Thermal decomposition of fatty acid chains during the supercritical methanol transesterification of soybean oil to biodiesel , 2012 .

[28]  P. Koske,et al.  Production of Nannochloris spec. (Chlorophyceae) in large-scale outdoor tanks and its use as a food organism in marine aquaculture , 1981 .

[29]  Meisam Tabatabaei,et al.  Fatty acids profiling: A selective criterion for screening microalgae strains for biodiesel production , 2013 .

[30]  J. Quesada-Medina,et al.  Synthesis of biodiesel from soybean oil using supercritical methanol in a one-step catalyst-free process in batch reactor , 2011 .

[31]  Trevor Platt,et al.  Mathematical formulation of the relationship between photosynthesis and light for phytoplankton , 1976 .

[32]  Jungmin Kim,et al.  Methods of downstream processing for the production of biodiesel from microalgae. , 2013, Biotechnology advances.

[33]  P. A. Rice,et al.  Supercritical biodiesel production and power cogeneration: technical and economic feasibilities. , 2010, Bioresource technology.