Lipid accumulation by a novel microalga Parachlorella kessleri R-3 with wide pH tolerance for promising biodiesel production

In this study, a new microalgal strain was isolated and identified as Parachlorella kessleri R-3, which could utilize a variety of organic and inorganic carbon and nitrogen sources. More importantly, it was found that strain R-3 can accumulate large amount of biomass and lipids in a wide pH range from 3 to 11, and it can gradually adjust the pH of the medium to near neutrality during the cultivation. At the optimal glucose concentration of 10 g L-1, sodium nitrate concentration of 0.8 g L-1 and initial pH of 7, the highest algal biomass of 6.90 g L-1, lipid content of 45.12 % and lipid productivity of 340.94 mg L-1 d-1 were achieved. In addition, C16:0 iso 3OH and C16:1 w7c alcohol were the predominant fatty acids components, which accounted for as high as 88.04 %. These showed the potential of the new microalgal strain for application in biodiesel production.

Automated summary

A new microalgal strain, Parachlorella kessleri R-3, was isolated and identified in this study, which demonstrated the ability to utilize various carbon and nitrogen sources. Furthermore, strain R-3 was capable of accumulating substantial biomass and lipids over a wide pH range and adjusting the medium pH to near neutrality during cultivation. The highest algal biomass of 6.90 g L-1, lipid content of 45.12%, and lipid productivity of 340.94 mg L-1 d-1 were achieved under optimal conditions of glucose concentration, sodium nitrate concentration, and initial pH. The predominant fatty acid components were C16:0 iso 3OH and C16:1 w7c alcohol, accounting for up to 88.04% of total fatty acids, indicating the potential application of this microalgal strain in biodiesel production.