Jiang Yiqi, Pu Xiaodong, Zheng Dan, Zhu Tao, Wang Shuang, Deng Liangwei, Wang Wenguo
1Biogas Institute of Ministry of Agriculture, Chengdu, 610041 People's Republic of China.
Key Laboratory of Development and Application of Rural Renewable Energy, Chengdu, 610041 People's Republic of China.
Biotechnol Biofuels. 2018 Apr 7;11:101. doi: 10.1186/s13068-018-1102-3. eCollection 2018.
Using liquid digestate from the biogas industry as a medium to culture lipid-producing microalgae is considered mutually beneficial for digestate valorization and for reducing the cost of microalgal cultivation. However, the low transmittance and high ammonium (NH-N) levels in liquid digestate negatively influence microalgae growth.
Struvite precipitation was used to pretreat liquid digestate. To obtain struvite-precipitated supernatant with an ideal transmittance, NH-N concentration, salinity, and N:P ratio for microalgal growth, there should be a 1:1.2:1.2 NH:Mg:PO molar ratio in the liquid digestate, with KHPO and MgCl added through continuous stirring. The addition and stirring was subsequently stopped when the pH reached 8.5. Of the nine tested microalgae species, exhibited the best growth in the supernatant. The biomass productivity and lipid content of cultured in the struvite-precipitated supernatant were 161.06 mg/l/days and 34.33%, respectively, which was higher than when cultured in the standard BG-11 medium. Moreover, the struvite-precipitated supernatant improved the accumulation of monounsaturated fatty acids and saturated fatty acids.
This study described a new way to combine liquid digestate treatment and microalgal biodiesel production. The struvite-pretreated liquid digestate can be used to culture for biodiesel production.
将沼气行业的液体沼渣用作培养产油微藻的培养基，被认为对沼渣的增值利用和降低微藻养殖成本具有互利作用。然而，液体沼渣的低透光率和高铵（NH-N）水平对微藻生长产生负面影响。
采用鸟粪石沉淀法对液体沼渣进行预处理。为了获得具有理想透光率、NH-N浓度、盐度和氮磷比以促进微藻生长的鸟粪石沉淀上清液，液体沼渣中NH:Mg:PO的摩尔比应为1:1.2:1.2，并通过持续搅拌添加KHPO和MgCl。当pH值达到8.5时，停止添加和搅拌。在测试的9种微藻中，[具体微藻名称未给出]在上清液中生长最佳。在鸟粪石沉淀上清液中培养的[具体微藻名称未给出]的生物量生产力和脂质含量分别为161.06毫克/升/天和34.33%，高于在标准BG-11培养基中培养时。此外，鸟粪石沉淀上清液提高了单不饱和脂肪酸和饱和脂肪酸的积累。
本研究描述了一种将液体沼渣处理与微藻生物柴油生产相结合的新方法。经鸟粪石预处理的液体沼渣可用于培养[具体微藻名称未给出]以生产生物柴油。
