Cai Yihui, Zhai Ligong, Fang Xiaoman, Wu Kangping, Liu Yuhuan, Cui Xian, Wang Yunpu, Yu Zhigang, Ruan Roger, Liu Tongying, Zhang Qi
State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, Jiangxi, China.
College of Food Engineering, Anhui Science and Technology University, Fengyang, 233100, Anhui, China.
Biotechnol Biofuels Bioprod. 2022 Oct 8;15(1):102. doi: 10.1186/s13068-022-02204-z.
Microalgae protein is considered as a sustainable alternative to animal protein in the future. Using waste for microalgal culture can upgrade low-value raw materials into high-value products, helping to offset the cost of microalgal protein production. In this study we explored the feasibility of using microalgae heterotrophic fermentation to convert broken rice hydrolysate (BRH) into protein.
The results showed that the increase of BRH supplemental ratio was beneficial to the increase of biomass production but not beneficial to the increase of intracellular protein content. To further improve protein production, the effect of C/N ratio on intracellular protein accumulation was studied. It was found that low C/N ratio was beneficial to the synthesis of glutamate in microalgae cells, which in turn promoted the anabolism of other amino acids and further the protein. When the C/N ratio was 12:1, the biomass productivity and protein content could reach a higher level, which were 0.90 g/L/day and 61.56%, respectively. The obtained Chlorella vulgaris biomass was rich in essential amino acids (41.80%), the essential amino acid index was as high as 89.07, and the lysine content could reach up to 4.05 g/100 g.
This study provides a theoretical basis and guidance for using Chlorella vulgaris as an industrial fermentation platform to convert broken rice into products with high nutritional value.
微藻蛋白被认为是未来动物蛋白的可持续替代品。利用废弃物进行微藻培养可将低价值原料升级为高价值产品，有助于抵消微藻蛋白生产的成本。在本研究中，我们探索了利用微藻异养发酵将碎米水解物（BRH）转化为蛋白质的可行性。
结果表明，提高BRH补充比例有利于生物量的增加，但不利于细胞内蛋白质含量的增加。为进一步提高蛋白质产量，研究了碳氮比对细胞内蛋白质积累的影响。发现低碳氮比有利于微藻细胞内谷氨酸的合成，进而促进其他氨基酸的合成代谢以及蛋白质的合成。当碳氮比为12:1时，生物量生产力和蛋白质含量可达到较高水平，分别为0.90 g/L/天和61.56%。所获得的小球藻生物量富含必需氨基酸（41.80%），必需氨基酸指数高达89.07，赖氨酸含量可达4.05 g/100 g。
本研究为利用小球藻作为工业发酵平台将碎米转化为高营养价值产品提供了理论依据和指导。
