Chlorella sp. HS2, which previously showed excellent performance in phototrophic cultivation and has tolerance for wide ranges of salinity, pH, and temperature, was cultivated heterotrophically. However, this conventional medium has been newly optimized based on a composition analysis using elemental analysis and ICP-OES. In addition, in order to maintain a favorable dissolved oxygen level, stepwise elevation of revolutions per minute was adopted. These optimizations led to 40 and 13% increases in the biomass and lipid productivity, respectively (7.0 and 2.25 g l^-1d^-1 each). To increase the lipid content even further, 12 h heat shock at 50°C was applied and this enhanced the biomass and lipid productivity up to 4 and 17% respectively (7.3 and 2.64 g l^-1d^-1, each) relative to the optimized conditions above, and the values were 17 and 14% higher than ordinary lipid-accumulating N-limitation (6.2 and 2.31 g l^-1d^-1). On this basis, heat shock was successfully adopted in novel Chlorella sp. HS2 cultivation as a lipid inducer for the first time. Considering its fast and cost-effective characteristics, heat shock will enhance the overall microalgal biofuel production process.

中文翻译：

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增强小球藻的脂质生产。HS2 使用序列优化和热冲击。

小球藻_ HS2 以前在光养栽培中表现出优异的性能，对盐度、pH 和温度的宽范围具有耐受性，现在被异养栽培。然而，基于使用元素分析和 ICP-OES 的成分分析，这种传统介质已被重新优化。此外，为了保持有利的溶解氧水平，采用逐步提高每分钟转数。这些优化分别导致生物量和脂质生产力增加 40% 和 13%（各 7.0 和 2.25 gl ^-1 d ^-1）。为了进一步增加脂质含量，在 50°C 下进行 12 小时热激，这将生物量和脂质生产力分别提高了 4% 和 17%（7.3 和 2.64 gl ^-1d ^-1，每个）相对于上述优化条件，并且该值比普通脂质积累N-限制（6.2和2.31 gl ^-1 d ^-1）高17％和14％。在此基础上，热休克成功应用于新型小球藻。HS2 首次作为脂质诱导剂进行培养。考虑到其快速和具有成本效益的特性，热激将增强微藻生物燃料的整体生产过程。