A possible source of biological material for the production of biodiesel is represented by microalgae, in particular by their lipid content. The aim of the present work was to optimize culture medium composition for i...A possible source of biological material for the production of biodiesel is represented by microalgae, in particular by their lipid content. The aim of the present work was to optimize culture medium composition for improving growth and lipid content of green microalgae Chlorella sorokiniana, Scenedesmus acuminatus and blue green Cyanobacterium aponicum. Lipids were quantitatively determined by spectrofluorometric method using Nile red flurometric stain. Initially, the effect of two different medium types, Bold’s and optimized culture medium (OCM), four types of carbon source (glucose and sodium acetate, molasses, glycerol, control) and four nitrogen concentrations (100%, -75%, -50%, -25%) on the enhancement of biomass and lipid content and lipid productivity were studied;indeed, optimized culture medium significantly improved growth, CDW for three microalgae, beside increasing lipid content and lipid productivity for S. acuminatus and C. aponicum by 7.5 and 5 folds respectively at 25th day compared to Bold’s medium. Moreover, 25% nitrogen deficient medium significantly increased lipid content and lipid productivity for both C. sorokiniana and C. aponicum at 2nd week of re-propagation to 10.6 and 2.6 folds over control (100% nitrogen). While S. acuminatus recorded the significant lipid content & productivity at 2nd week under recommended nitrogen dose in medium (100% N) by 4.4 folds over 25% deficient medium. Meanwhile 0.3% glycerol medium enhanced CDW, lipid content of S. acuminatus to 1.68 gL-1. While C. sorokiniana and C. aponicum recorded significant CDW under 0.3% acetate medium 1.37 and 0.76 gL-1. C. aponicum exhibited no growth under glycerol medium. The highest lipid content and lipid productivity were obtained under glycerol medium for C. sorokiniana and S. acuminatus (64.3 and 52.8 mg·g·gǃ·dǃ).展开更多
In recent years, photosynthetic microalgae regained attention for biodiesel production. For efficient utilization of microalgae, a number of criteria including a strain with high biomass and lipid productivities and e...In recent years, photosynthetic microalgae regained attention for biodiesel production. For efficient utilization of microalgae, a number of criteria including a strain with high biomass and lipid productivities and employment of effective and reliable methods for oil extraction from the obtained biomass should be met. Recently, we have isolated and identified three thermo-resistant green microalgae strains, namely;Scenedesmus sp. ME02, Hindakia tetrachotoma ME03 and Mic-ractinium sp. ME05. In this study, we compared percent lipid content of thermos-tolerant mic-roalgal strains using the following solvent extraction methods: Soxhlet, Bligh and Dyer and Folch methods with or without assisted cell disruption techniques including lyophilization, homogenization, ultrasonication, bead and microwave-assisted. The highest increase in lipid yield was obtained with a combination of lyophilization and ultrasonication techniques together with Soxhlet method: 27% of total dry weight for Micractinium sp. ME05. We conclude that lyophilization and ultrasonication are effective assistance methods for lipid extraction from thermo-resistant microalgae.展开更多
文摘A possible source of biological material for the production of biodiesel is represented by microalgae, in particular by their lipid content. The aim of the present work was to optimize culture medium composition for improving growth and lipid content of green microalgae Chlorella sorokiniana, Scenedesmus acuminatus and blue green Cyanobacterium aponicum. Lipids were quantitatively determined by spectrofluorometric method using Nile red flurometric stain. Initially, the effect of two different medium types, Bold’s and optimized culture medium (OCM), four types of carbon source (glucose and sodium acetate, molasses, glycerol, control) and four nitrogen concentrations (100%, -75%, -50%, -25%) on the enhancement of biomass and lipid content and lipid productivity were studied;indeed, optimized culture medium significantly improved growth, CDW for three microalgae, beside increasing lipid content and lipid productivity for S. acuminatus and C. aponicum by 7.5 and 5 folds respectively at 25th day compared to Bold’s medium. Moreover, 25% nitrogen deficient medium significantly increased lipid content and lipid productivity for both C. sorokiniana and C. aponicum at 2nd week of re-propagation to 10.6 and 2.6 folds over control (100% nitrogen). While S. acuminatus recorded the significant lipid content & productivity at 2nd week under recommended nitrogen dose in medium (100% N) by 4.4 folds over 25% deficient medium. Meanwhile 0.3% glycerol medium enhanced CDW, lipid content of S. acuminatus to 1.68 gL-1. While C. sorokiniana and C. aponicum recorded significant CDW under 0.3% acetate medium 1.37 and 0.76 gL-1. C. aponicum exhibited no growth under glycerol medium. The highest lipid content and lipid productivity were obtained under glycerol medium for C. sorokiniana and S. acuminatus (64.3 and 52.8 mg·g·gǃ·dǃ).
文摘In recent years, photosynthetic microalgae regained attention for biodiesel production. For efficient utilization of microalgae, a number of criteria including a strain with high biomass and lipid productivities and employment of effective and reliable methods for oil extraction from the obtained biomass should be met. Recently, we have isolated and identified three thermo-resistant green microalgae strains, namely;Scenedesmus sp. ME02, Hindakia tetrachotoma ME03 and Mic-ractinium sp. ME05. In this study, we compared percent lipid content of thermos-tolerant mic-roalgal strains using the following solvent extraction methods: Soxhlet, Bligh and Dyer and Folch methods with or without assisted cell disruption techniques including lyophilization, homogenization, ultrasonication, bead and microwave-assisted. The highest increase in lipid yield was obtained with a combination of lyophilization and ultrasonication techniques together with Soxhlet method: 27% of total dry weight for Micractinium sp. ME05. We conclude that lyophilization and ultrasonication are effective assistance methods for lipid extraction from thermo-resistant microalgae.
