The high cost of carbon source limits the heterotrophic culture of Chlorella. In this study, broken rice was hydrolyzed into glucose. Then, the broken rice hydrolysate (BRH) was utilized for heterotrophic cultivation of C. vulgaris instead of glucose. Results showed that algal cells released H+ when they consumed NH4+, leading to a sharp decrease in pH. Growth inhibition by acid could be avoided by using a pH buffer. Adding alkaline reagents intermittently during culture could not only reduce the amount of pH stabilizer but also obtain increased biomass production. When using Tris as pH stabilizer, the biomass productivity of C. vulgaris in BRH was the largest (1.01 g/L/d), followed by NaOH (1.00 g/L/d), and Na2CO3 (0.95 g/L/d). Using BRH instead of glucose for heterotrophic cultivation of C. vulgaris could save 89.58% of the cost of culture medium. This study developed a novel strategy for cultivating C. vulgaris heterotrophically using BRH.
Bibliographical noteFunding Information:
This research was supported by the National Natural Science Foundation of China (21878237, 21878139, 51708308, 21767017 and 22066016) in China; the Key Research and Development Program of Jiangxi Province (20181BAB206030, 2020BAB203012 and 20181BBF60026), the research project of State Key Laboratory of Food Science and Technology, Nanchang University (Project No. SKLF-ZZB-201915 and 201722) in China; the Post-doctoral Innovative Talents Support Program (BX20190147); and the selected funding for post-doctoral research projects in Jiangxi Province (2019KY04).
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- Broken rice hydrolysate
- Carbon source
- Chlorella vulgaris
- Heterotrophic culture