Alkaline environments are abundant globally and cause damage to most organisms, while some microalgae can grow well and accumulate lipids under those conditions. Here the mechanisms of alkali resistance and lipid accumulation in the alkaliphilic microalgae Chlorella sp. BLD were explored using physiological-biochemical and transcriptome analysis. When cultivated at alkaline pH, Chlorella sp. BLD exhibited good alkali-resistance ability and increased biomass (0.97g L^-1). The biochemical composition of Chlorella sp. BLD changed significantly (lipid content increased 39% and protein content decreased 19.5%) compared with pH 7.5. Through transcriptome analysis, we found that pathways related to carbon metabolism such as photosynthesis, glycolysis, and the TCA cycle were significantly regulated under alkaline conditions. Genes that encoding the key enzyme in carbon-related metabolism such as Rubisco, AMY, PK, ME, CS, ACAT, KAS, and DGAT were identified. Transcriptional regulation of these genes results in carbon flow switching from starch and protein to cell wall metabolism, organic acid synthetic and lipid accumulation in response to alkaline conditions. These results reveal the alkali resistance mechanism of Chlorella sp. BLD and provide a theoretical basis for microalgae oil production under alkaline conditions.

碱性环境在全球范围内十分丰富，会对大多数生物造成破坏，而某些微藻可以在这些条件下生长良好并积聚脂质。在这里，碱度微藻小球藻的抗碱性和脂质积累的机制。使用生理生化和转录组分析探索BLD。在碱性pH下培养时，小球藻（Chlorella sp。）BLD具有良好的耐碱性和生物量（0.97g L ^-1）。小球藻的生化组成sp。与pH 7.5相比，BLD发生了显着变化（脂质含量增加了39％，蛋白质含量减少了19.5％）。通过转录组分析，我们发现在碱性条件下，与碳代谢相关的途径（例如光合作用，糖酵解和TCA循环）受到显着调节。鉴定了编码碳相关代谢中关键酶的基因，例如Rubisco，AMY，PK，ME，CS，ACAT，KAS和DGAT。这些基因的转录调节导致碳流从淀粉和蛋白质向细胞壁代谢，有机酸合成和脂质积累的碳流转换，以响应碱性条件。这些结果揭示了小球藻的抗碱性机制。并为碱性条件下微藻油的生产提供了理论基础。