Exogenous l -proline improved Rhodosporidium toruloides lipid production on crude glycerol
- PDF / 1,388,771 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 73 Downloads / 191 Views
Biotechnology for Biofuels Open Access
RESEARCH
Exogenous l‑proline improved Rhodosporidium toruloides lipid production on crude glycerol Rasool Kamal1,3, Yuxue Liu1,3, Qiang Li1,3, Qitian Huang1,2, Qian Wang1,2, Xue Yu1,2 and Zongbao Kent Zhao1,2*
Abstract Background: Crude glycerol as a promising feedstock for microbial lipid production contains several impurities that make it toxic stress inducer at high amount. Under stress conditions, microorganisms can accumulate l-proline as a safeguard. Herein, l-proline was assessed as an anti-stress agent in crude glycerol media. Results: Crude glycerol was converted to microbial lipids by the oleaginous yeast Rhodosporidium toruloides CGMCC 2.1389 in a two-staged culture mode. The media was supplied with exogenous l-proline to improve lipid production efficiency in high crude glycerol stress. An optimal amount of 0.5 g/L l-proline increased lipid titer and lipid yield by 34% and 28%, respectively. The lipid titer of 12.2 g/L and lipid content of 64.5% with a highest lipid yield of 0.26 g/g were achieved with l-proline addition, which were far higher than those of the control, i.e., lipid titer of 9.1 g/L, lipid content of 58% and lipid yield of 0.21 g/g. Similarly, l-proline also improved cell growth and glycerol consumption. Moreover, fatty acid compositional profiles of the lipid products was found suitable as a potential feedstock for biodiesel production. Conclusion: Our study suggested that exogenous l-proline improved cell growth and lipid production on crude glycerol by R. toruloides. The fact that higher lipid yield as well as glycerol consumption indicated that l-proline might act as a potential anti-stress agent for the oleaginous yeast strain. Keywords: Anti-stress agent, Crude glycerol, Microbial lipids, Rhodosporidium toruloides, Two- stage culture Background Biodiesel is a renewable alternative to fossil fuels [1]. Its global production has increased dramatically in the past decade [2]. Unlike fossil fuels, biodiesel is eco-friendly and non-toxic with less sulfur and carbon dioxide emissions [3]. However, biodiesel production generates about 10% crude glycerol as a by-product, which contains several impurities at the risk of disposal [4]. As a result, several European countries treat it as industrial wastewater
*Correspondence: [email protected] 1 Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, People’s Republic of China Full list of author information is available at the end of the article
[5]. For this reason, the conversion of crude glycerol to value-added products is essential [1]. The current biodiesel technology is based on plant oils and animal fats, but these resources are limited. The lipid produced by oleaginous microorganisms is known to be a novel feedstock for biodiesel production with similar fatty acids composition to that as plants oil [6]. Moreover, microbial lipid has several leads over plants oil including; free of weather and land use, have high productivity, short produ
Data Loading...
