Abstract

Microalgal biodiesel as a substitute for fossil energy has attracted extensive attention. However, the high cost of microalgae cultivation limits the industrial production of microalgal biodiesel. The co-culture system may offer a means to increase microalgae’s biomass production. In this study, Streptomyces strains were selected to construct and optimize co-culture systems with Monoraphidium sp. HDMA-11 and the algal cell biomass, lipid content, phycocyanin content, starch content, and fatty acid composition were determined. The results showed that Streptomyces nojiriensis significantly promoted Monoraphidium sp. HDMA-11 growth and a co-culture system were established. Orthogonal experiments showed that the Monoraphidium sp. HDMA-11 biomass was further increased when the initial culture pH was 7.5, the inoculation time of Streptomyces strain supernatants was 36 h, the volume ratio of microalgal actinomycetes was 1:1, and no additional acetic acid was added. Under these conditions, compared with monocultured Monoraphidium sp. HDMA-11, the cell biomass and lipid productivity of the co-culture system increased by 525.8 and 155.1%, respectively. These results suggest that S. nojiriensis supernatant potentially enhances microalgae biomass and may represent a new method to improve microalgae growth.

摘要

微藻生物柴油作为化石能源的替代品受到广泛关注。然而，微藻养殖的高成本限制了微藻生物柴油的工业化生产。共培养系统可以提供一种增加微藻生物量产量的方法。在本研究中，选择链霉菌菌株构建和优化与Monoraphidium sp. 的共培养系统。测定了 HDMA-11 和藻类细胞生物量、脂质含量、藻蓝蛋白含量、淀粉含量和脂肪酸组成。结果表明，Streptomyces nojiriensis显着促进了Monoraphidium sp. 建立了 HDMA-11 生长和共培养系统。正交实验表明单针藻 当初始培养pH为7.5、链霉菌菌株上清液接种时间为36 h、微藻放线菌体积比为1:1、不额外添加乙酸时，HDMA-11生物量进一步增加。在这些条件下，与单一培养的Monoraphidium sp。HDMA-11、共培养系统的细胞生物量和脂质生产力分别增加了525.8和155.1%。这些结果表明，S. nojiriensis上清液可能会增强微藻生物量，并可能代表一种改善微藻生长的新方法。