Abstract:

The effects of different diethanolamine concentrations on growth, CO₂ biofixation, and lipid accumulation of eminent microalga Coccomyxa subellipsoidea C-169 was explored. The results showed that the appropriate concentration of DEA could significantly improve CO₂ biofixation and lipid accumulation efficiency. The highest levels of biomass, CO₂ biofixation rate, lipid content and lipid productivity were achieved to 0.97g/L, 225.98mg/(L·d), 64.33%, and 59.9mg/(L·d) under 40mg/L DEA, respectively, which were separately 1.64-, 1.64-, 1.15- and 1.27-fold more than that without DEA group. Exogenous DEA improved gas-liquid mass transfer coefficient and CO₂ mass transfer efficiency, and consequently enhanced the proportion of available inorganic carbon sources for C. subellipsoidea. Synchronously, exogenous DEA up-regulated 1,5-bisphosphate carboxylase Rubisco and carbonic anhydrase CA in carbon fixation pathway, and consequently improved CO₂ bio-fixation of C. subellipsoidea. DEA also up-regulated acetyl-coa carboxylase ACCase in lipid pathway and down-regulated pyruvate carboxylase PEPC in ACCase competition pathway to strengthen lipid accumulation in C. subellipsoidea. These results provided a basis for industrial CO₂ emission reduction and renewable energy development of C. subellipsoidea.

Key words: diethanolamine, biomass, carbon dioxide, lipids, biodiesel

摘要：

以优良藻株胶球藻Coccomyxa subellipsoidea C-169为受试对象，探究不同二乙醇胺（DEA）浓度对胶球藻固定CO₂及积累油脂的影响。结果表明，适宜浓度DEA可显著提高胶球藻固定CO₂和积累油脂效率。在40mg/L DEA条件下，胶球藻生物量、CO₂固定效率、油脂含量、油脂产率均达到最大值为0.97g/L、225.98mg/(L·d)、64.33%、59.9mg/(L·d)，分别较无DEA对照提高了1.64倍、1.64倍、1.15倍和1.27倍。外源DEA作用提高了体系气液传质系数，增强CO₂传质效率，使得胶球藻可用无机碳源比例增加，同时上调固碳路径Rubisco和CA加强胶球藻固定CO₂，上调脂肪酸路径ACCase以及下调ACCase竞争路径PEPC为油脂合成积累提供前体和能量，从而协同强化了胶球藻固定CO₂和积累油脂。本文研究结果为工业化胶球藻CO₂生物减排及可再生能源开发提供依据。

关键词: 二乙醇胺, 生物质, 二氧化碳, 油脂, 生物柴油