High yield production of lipid and carotenoids in a newly isolated Rhodotorula mucilaginosa by adapting process optimization approach

Abstract

Rhodotorula sp. is a robust microbe, which can synthesize a wide range of products such as lipids and carotenoids. In the present study, we have attempted to enhance the production of lipids and carotenoids from a newly isolated Rhodotorula mucilaginosa using a process optimization approach. Among the carbon source screened, glucose showed enhanced lipid and carotenoid production of 46.19% (w/w) and 36.2 mg/g, respectively. The low C/N has influenced lipid production by 43.5% and the high C/N ratio favored carotenoid production (41.06 µg/g). The sodium acetate with 1.5% (w/v) concentration showed a lipid content of 48.28% and carotenoid of 41.16 mg/g. Further with the optimum levels of RPM (180), pH (6), and temperature (30 °C), the maximum lipid and carotenoid were found to be 51.89%, and 43.34 µg/g, respectively. In a batch bioreactor, MSM medium with sodium acetate showed a maximum lipid content of 54%. The lipid and carotenoid were successfully characterized by laser Raman spectroscopy, a label-free method and the FAME analysis clearly showed the high content of palmitic acid (C16:0) 21.05 (% w/w), oleic acid (C18:1) 56.18 (%w/w) and linoleic acid (C18:2) 12.25 (% w/w), which is suitable for biodiesel preparation.

Graphical Abstract

Highlights

• The process parameters were fine-tuned using PCA to get maximum lipid and carotenoid yield.

• Low C/N ratio elevated lipid content while a high C/N ratio induced carotenoids.

• Batch bioreactor using sodium acetate resulted in 54% of lipid content.

• Simultaneous estimation of lipid and carotenoid was done using Raman laser spectroscopy

• The lipid profiling using FAME showed excellent biodiesel characteristics.

Keywords:

• Rhodotorula mucilaginosa
• lipids
• carotenoid
• process optimization
• principal component analysis

Acknowledgement

The authors are thankful to the Department of Biotechnology, Indian Institute of Technology Guwahati for providing facilities for conducting experiments. Also, the authors are grateful the to central instrument facility (CIF) IIT Guwahati for providing the facility of Laser Micro Raman Spectroscopic.

Authors’ contribution

Ravi Gadela: Methodology, Analysis, Writing – original draft, Ashish A Prabhu: Data curation, Validation, Writing – original draft. Kannan Pakshirajan: Conceptualization, Supervision, review & editing. Veeranki Venkata Dasu: Conceptualization, Supervision, Resources, review & editing. All authors read and approved the final manuscript.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.