Lipid production capacity of a newly characterized cyanobacterial strain Synechocystis sp. MH01: A comparative performance evaluation of cyanobacterial lipid-based biodiesel

Document Type: Research Paper

Authors

1 Department of Microbiology, Faculty of Biological Sciences, Alzahra University, P.O. Box 1993893973, Tehran, Iran,

2 2Department of Biotechnology, Faculty of Biological Sciences, Alzahra University, P.O. Box 1993893973, Tehran, Iran

3 Biofuel Research Team (BRTeam), Microbial Biotechnology and Biosafety Department, Agricultural Biotechnology Research Institute of Iran (ABRII), P.O. Box 31535-189

4 Department of Chemistry, Faculty of Science, Alzahra University, P.O. Box 1993893973, Tehran, Iran

5 Shahid Chamran University of Ahvaz, Faculty of Agronomy and Plant Breeding, Ahvaz, Iran.

Abstract

A cyanobacterial strain was isolated from waterfalls located in Northern Iran and identified as Synechocystis sp. MH01 using 16S rRNA gene sequence analysis. The autotrophic cultivation of cyanobacterial strain in BG11 medium resulted in biomass and lipid productivity of 109 mgl-1day-1 and 22.89 mgl-1day-1, respectively. Further, the effects of different carbohydrates and amino acids on growth and accumulation of lipids by Synechocystis sp. MH01 were carefully investigated. The mixotrophic cultivation of Synechocystis sp. MH01 in sucrose-containing BG11 medium resulted in approximately 1.8 and 1.22 fold increase in biomass and lipid productivity compared with an autotrophic condition. Addition of glycine to BG11 medium leads to an up to ~1.3 and ~1.18 fold increase in biomass and lipid productivity compared with control subjects. Evaluation of different physicochemical and nutritional parameters showed a higher biomass and lipid productivity under the following conditions: light/dark period (24-0) (BP: 75 mgl-1d-1, LP: 24 mgl-1d-1), sodium thiosulphate 1 mM (BP: 125, LP: 32.42), initial pH: 7 (BP: 109, LP: 22.89), sucrose %1 (BP: 194, LP: 71.93), glycine 0.1% (BP: 130, LP: 40), biotin (BP: 155, LP: 26.85) and temperature 30°C (BP: 111, LP: 33.42). The fatty acid profiles of the selected cyanobacterial strain grown under these conditions were determined through gas chromatography (GC) analysis and compared with control subjects to further validate biodiesel quality. Fatty acid profiles of the cyanobacterial cell were used to estimate biodiesel quality parameters including saturated fatty acid (%), monounsaturated fatty acid (%), polyunsaturated fatty acid (%), degree of unsaturation, saponification value (mgg-1), cetane number, long chain saturated factor, cold filter plugging point (°C), cloud point (°C), pour point (°C), allylic position equivalent, bis-allylic position equivalent, oxidation stability (h), higher heating value, kinematic viscosity (mm2s-1), density (g(cm3)-1). The novelty of this research is evaluating the effect of different vitamins on cyanobacteria lipid productivity and growth. In most researches, only effect of vitamin B12 was evaluated. Evidence collected during this study suggests that the cyanobacterium Synechocystis sp. MH01 can be a promising feedstock for bioenergy generation.

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