Increasing lipid production from Zygosaccharomyces siamensis AP1 in molasses substrate using sequencing batch method

Abstract

Yeasts are considered potential lipid producers to substitute oil-producing plants. Previous study succeeded in isolating Zygosaccharomyces siamensis AP1 from Indonesia which was able to accumulate 19% lipid. The strain, however, was not optimized for high cell density growth which is required for industry-level. In this study, efforts were made to increase cell density and lipid production of Z. siamensis AP1 using molasses as carbon source and implementing sequencing batch method. The yeast was grown in various combinations of carbon and nitrogen sources. The C:N ratio of the best substrate combination is then optimized. Afterwards, batch and sequencing batch methods were applied in fermentation with various concentrations (20–480 g/L) of molasses. The results show that lipid produced using molasses was slightly higher compared to using glucose, 0.21 g/L and 0.19 g/L respectively, with the same nitrogen source. Combination of molasses and ammonium sulfate with C:N ratio 70:1 gave the highest lipid (0.28 g/L). Sequencing batch able to increase cell density 2.4-fold compared to batch method. This study was the first to report that sequencing batch application with molasses as carbon source can increase lipid production from Z. siamensis. Further study to optimize medium composition for sequencing batch is suggested.

Keywords:

• C:N ratio
• cell density
• low-cost substrate
• oleaginous yeast
• optimization

Acknowledgments

We would like to thank you PT Madubaru Yogyakarta for providing us with molasses.

Authors’ contributions

This study was part of bachelor theses of Anugrah Badrani (AB) and Annisa Fauziyah (AF) which were supervised by Miftahul Ilmi (MI). AB and AF obtained and analyzed the data, while MI analyzed the data and wrote the manuscript.

Additional information

Funding

The research was funded by Universitas Gadjah Mada through RTA Grant [nr. 3143/UN1.P.III/DIT-LIT/PT/2021].