Optimization of Lipid Production by Schizochytrium limacinum Biomass Modified with Ethyl Methane Sulfonate and Grown on Waste Glycerol

Abstract

One of the most promising avenues of biofuel research relates to using waste as a starting feedstock to produce liquid or gaseous energy carriers. The global production of waste glycerol by the refinery industry is rising year after year. The aim of the present study was to examine the effect of ethyl methane sulfonate (EMS) on the growth rates and intracellular lipid accumulation in heterotrophically-cultured Schizochytrium limacinum microalgae, grown on waste glycerol as the carbon source. The strain S. limacinum E20, produced by incubating a reference strain in EMS for 20 min, was found to perform the best in terms of producing biomass (0.054 gDW/dm3·h) and accumulating intracellular bio-oil (0.021 g/dm3·h). The selected parameters proved to be optimal for S. limacinum E20 biomass growth at the following values: temperature 27.3 °C, glycerol level 249.0 g/dm3, oxygen in the culture 26%, and yeast extract concentration 45.0 g/dm3. In turn, the optimal values for lipid production in an S. limacinum E20 culture were: temperature 24.2 °C, glycerol level 223.0 g/dm3, oxygen in the culture 10%, and yeast extract concentration 10.0 g/dm3. As the process conditions are different for biomass growth and for intracellular lipid accumulation, it is recommended to use a two-step culture process, which resulted in a lipid synthesis rate of 0.41 g/dm3·h.

A Thermosiphon Photobioreactor for Photofermentative Hydrogen Production by Rhodopseudomonas palustris

“…Crude glycerol, a by-product of the biodiesel industry, has gained increasing attention as a substrate in biological waste to value-added product processes—some of these processes include biogas production by anaerobic digestion [ 35 , 36 , 37 ], lipid production [ 38 ], and photofermentative hydrogen production [ 7 ], with Pott et al [ 7 ] reporting a conversion efficiency (crude glycerol to hydrogen gas) that is close to 90% of the theoretical maximum when using R. palustris . The combination of industrial waste streams as a carbon substrate and a cost-efficient PBR would not only decrease the cost of photofermentative hydrogen production [ 34 ], but also aid in moving towards sustainable hydrogen production and green energy.…”

Waste Glycerol in the Biosynthesis of Liquid Fuels and Other Value-Added Products – a Review

“…Talbierz et al [88] investigated the effect of ethyl methanesulfonate (EMS) on the growth rate and intracellular lipid accumulation in the heterotrophically cultivated microalga Schizochytrium limacinum, which was cultivated on waste glycerol as a carbon source. The strain S. limacinum E20, which was produced by incubating the reference strain in EMS for 20 minutes, showed the best results in biomass production (0.054 gsm/L•h) and intracellular bio-oil accumulation (0.021 g/L•h).…”

“…The optimum parameters for lipid production in the S. limacinum E20 culture were: temperature 24.2°C, glycerol concentration 223.0 g/L, oxygen in the culture 10% and yeast extract concentration 10.0 g/L. Due to the different conditions of biomass growth and intracellular lipid accumulation, it is recommended to use a two-stage culture process, which resulted in a lipid synthesis rate of 0.41 g/L•h [88].…”

The Biosynthesis of Liquid Fuels and Other Value-Added Products Based on Waste Glycerol—A Comprehensive Review and Bibliometric Analysis

“…Talbierz et al [114] investigated the effect of ethyl methanesulfonate (EMS) on the growth rate and intracellular lipid accumulation in Schizochytrium limacinum microalga heterotrophically cultivated on waste glycerol as a carbon source. The strain S. limacinum E20, which was produced by incubating the reference strain in EMS for 20 min, showed the best results in biomass production (0.054 gsm/L•h) and intracellular bio-oil accumulation (0.021 g/L•h).…”