Effect of cultivation mode on the production of docosahexaenoic acid by Tisochrysis lutea

Hao Hu,Jia-Yun Li,Hou-Feng Wang,Xiao-Fei Shen,Lin-Lin Ma,Raymond Jianxiong Zeng

doi:10.1186/s13568-018-0580-9

Abstract

In this study, Tisochrysis lutea was cultivated in mixotrophic and heterotrophic cultures with glycerol as a carbon source and with glucose and acetate for comparison; autotrophic cultivation was the control group without a carbon source. It was found that T. lutea used glycerol and did not use glucose and acetate under mixotrophy. Mixotrophy slightly elevated the docosahexaenoic acid (DHA) and total fatty acids (TFA) content in the dry-weight and enhanced the DHA and TFA production in medium (41.3 and 31.9% respectively) at the end of a 16-day cultivation, while heterotrophy reduced the DHA content and TFA production. Under the mixotrophy, the glycerol contribution to the DHA production (16.19 mg/L) and the TFA production (97.8 mg/L) was not very high and the DHA yield [2.63% chemical oxygen demand (COD)] and TFA yield (13.1% COD) were also very low. Furthermore, T. lutea using glycerol had a period of adaptation, indicating that T. lutea was not an ideal microalga for organic carbon utilization.

Highlights

Docosahexaenoic acid (DHA) has a high medical and nutritional value; it promotes visual acuity and neural development (Boelen et al 2013), and reduces the risk of some diseases such as cardiovascular, arthritis, diabetes, and obesity related breast cancer (Biscione et al 2007; Lee et al 2012; Manni et al 2017)
The DHA content of T. lutea is much higher than other microalgae such as Phaeodactylum tricornutum (0.98% total fatty acids (TFAs)) (Qiao et al 2016), Isochrysis galbana (6.84% TFAs) (Liu et al 2013), Pyramimonas sp. (5.8% TFAs), and Pavlova lutheri (9.6% TFAs) (Guiheneuf and Stengel 2013)
The effect of the N:P ratio on the DHA content of T. lutea was studied by Rasdi and Qin (2015) and the results indicated that N:P = 20:1 enhanced the DHA content to 8.1% of TFAs

Summary

Introduction

Docosahexaenoic acid (DHA) has a high medical and nutritional value; it promotes visual acuity and neural development (Boelen et al 2013), and reduces the risk of some diseases such as cardiovascular, arthritis, diabetes, and obesity related breast cancer (Biscione et al 2007; Lee et al 2012; Manni et al 2017). Tisochrysis lutea has been recognized as one of the most suitable species for DHA production due to its fast growth (Alkhamis and Qin 2016) and high DHA content [12–14% in total fatty acids (TFAs)] (Tzovenis et al 1997, 2003). The DHA content of T. lutea is much higher than other microalgae such as Phaeodactylum tricornutum (0.98% TFAs) (Qiao et al 2016), Isochrysis galbana (6.84% TFAs) (Liu et al 2013), Pyramimonas sp. The effect of the N:P ratio on the DHA content of T. lutea was studied by Rasdi and Qin (2015) and the results indicated that N:P = 20:1 enhanced the DHA content to 8.1% of TFAs

Methods

Results

Conclusion