Improved lipid and biomass productivities in Chlorella vulgaris by differing the inoculation medium from the production medium

Document Type: Research Paper

Authors

Department of Chemical Engineering, Ferdowsi University of Mashhad, Azadi Square, Pardis Campus, 91779-48944, Mashhad, Iran.

Abstract

Improvement of biomass and lipid productivities is now one of the main concerns in commercialization of microalgae cultivation as a feedstock for algal biofuel production. Conventional photoautotrophic processes using well-studied and rich in oil strain of Chlorella vulgaris are not able to meet such demands. A new strategy of inoculating algae production medium with cells grown in a different medium from the production medium was proposed herein. More specifically, when SH4 was used as production medium and N8 was used as inoculation medium, biomass and lipid productivities increased by 2.33 folds and 1.44 fold, respectively, compared with when the production and inoculation media were the same, such as SH4. The findings of the present investigation showed that this cultivation scheme resulted in 52% increase in cell number and 54% increase in dry weight leading to improved productivities. Although by even considering this improvement, photoautotrophic cultivation of algae can hardly compete with the heterotrophic cultivation, the high cost of hydrocarbon supply required in large-scale heterotrophic processes marks the technique proposed in the present study as a promising approach for commercialization of algal biofuel production.

Graphical Abstract

Improved lipid and biomass productivities in Chlorella vulgaris by differing the inoculation medium from the production medium

Highlights

  • Using  different  media  for  inoculums  preparation and  microalgae  production  improved  lipid  and biomass productivities.

  • When  SH4  was  selected for inoculation  medium and  N8  was  selected  for  production  medium, 130% increase  in  biomass  productivity and  40% increase  in  lipid  productivity  was  observed.

  • Specific growth  rate  improved  by  differing inoculums  preparation  medium  from  production medium  and changed  from 0.0040 h-1 to 0.0122 h-1.  

Keywords