Rhodosporidium sp. DR37: a novel strain for production of squalene in optimized cultivation conditions

Shahryar Shakeri,Farshad Khoshbasirat,Mahmood Maleki

doi:10.1186/s13068-021-01947-5

Shahryar Shakeri, Farshad Khoshbasirat + Show 1 more

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https://doi.org/10.1186/s13068-021-01947-5

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Abstract

BackgroundRhodosporidium strain, a well-known oleaginous yeast, has been widely used as a platform for lipid and carotenoid production. However, the production of squalene for application in lipid-based biofuels is not reported in this strain. Here, a new strain of Rhodosporidium sp. was isolated and identified, and its potential was investigated for production of squalene under various cultivation conditions.ResultsIn the present study, Rhodosporidium sp. DR37 was isolated from mangrove ecosystem and its potential for squalene production was assessed. When Rhodosporidium sp. DR37 was cultivated on modified YEPD medium (20 g/L glucose, 5 g/L peptone, 5 g/L YE, seawater (50% v/v), pH 7, 30 °C), 64 mg/L of squalene was produced. Also, squalene content was obtained as 13.9% of total lipid. Significantly, use of optimized medium (20 g/L sucrose, 5 g/L peptone, seawater (20% v/v), pH 7, 25 °C) allowed highest squalene accumulation (619 mg/L) and content (21.6% of total lipid) in Rhodosporidium sp. DR37. Moreover, kinetic parameters including maximum specific cell growth rate (μmax, h−1), specific lipid accumulation rate (qp, h−1), specific squalene accumulation rate (qsq, h−1) and specific sucrose consumption rate (qs, h−1) were determined in optimized medium as 0.092, 0.226, 0.036 and 0.010, respectively.ConclusionsThis study is the first report to employ marine oleaginous Rhodosporidium sp. DR37 for accumulation of squalene in optimized medium. These findings provide the potential of Rhodosporidium sp. DR37 for production of squalene as well as lipid and carotenoids for biofuel applications in large scale.Graphic abstract

Highlights

Rhodosporidium strain, a well-known oleaginous yeast, has been widely used as a platform for lipid and carotenoid production
Lipid and carotenoids production has been widely studied in Rhodosporidium species
This oleaginous yeast strain is currently being used for production of lipids in large-scale bioreactors

Summary

Introduction

Rhodosporidium strain, a well-known oleaginous yeast, has been widely used as a platform for lipid and carotenoid production. Microbial strains are capable of producing pollutant-free, low-cost, high-quality and sustainable squalene source as a major interest to lipid-based biofuels industries [12]. For these reasons, screening experiments and metabolic or bioprocess engineering have been used for isolation of naturally squalene producing microorganisms or improvement of squalene production in engineered microbes [11, 13, 14]. A protist (Aurantiochytrium) and a yeast (Pseudozyma) strain have been reported for their potential to produce high amount of squalene [16, 17]. High squalene producing yeastlike strains of Pseudozyma were isolated and identified, which are potential candidates for commercial production of squalene [16, 23]

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