Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China; School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China.
Environ Pollut. 2020 Oct;265(Pt A):114854. doi: 10.1016/j.envpol.2020.114854. Epub 2020 May 27.
Waste streams have emerged as potential feedstocks for biofuel production via microbial bioconversion. Metabolic engineering of the microalga Phaeodactylum tricornutum in its lipid biosynthetic pathways has been conducted with an aim to improve lipid production. However, there has been only limited achievement in satisfying biofuel demands by utilising extracellular organic carbons from low-cost waste streams. Herein, we present a successive staged cultivation mode, based on a previously engineered strain that co-overexpresses two key triacylglycerol biosynthesis genes. We first optimised microalgal biomass and lipid production by using food waste hydrolysate and crude glycerol as the cultivation media. Food waste hydrolysate (5% v/v) is a low-cost organic carbon source for enhanced microalgal biomass production, and the resulting lipid concentration was 1.08-fold higher with food-waste hydrolysate than that of the defined medium. Additionally, the resultant lipid concentration after using crude glycerol (100 mM) was 1.24-fold higher than that using the defined medium. Two carbon feeding modes (hybrid and sequential) were also performed to investigate the potential of engineered P. tricornutum with preliminary mechanistic analyses. The biodiesel properties of lipids produced in the hybrid mode were evaluated for potential application prospects. Collectively, this study demonstrates a waste stream utilisation strategy for efficient and sustainable microalgal biofuel production.
废物流已成为通过微生物生物转化生产生物燃料的潜在原料。通过对微藻三角褐指藻的脂质生物合成途径进行代谢工程改造，旨在提高脂质产量。然而，利用低成本废物流中的细胞外有机碳来满足生物燃料需求的成果有限。在此，我们提出了一种连续分阶段的培养模式，该模式基于之前共过表达两个关键三酰基甘油生物合成基因的工程菌株。我们首先使用食物垃圾水解物和粗甘油作为培养介质来优化微藻生物量和脂质生产。食物垃圾水解物（5%v/v）是一种低成本的有机碳源，可促进微藻生物量的生产，与使用定义培养基相比，使用食物垃圾水解物的脂质浓度提高了 1.08 倍。此外，使用粗甘油（100 mM）后的脂质浓度比使用定义培养基高 1.24 倍。还进行了两种碳进料模式（混合和顺序），以对初步进行了机理分析的工程三角褐指藻进行考察。对混合模式下产生的脂质的生物柴油特性进行了评估，以考察其潜在的应用前景。总的来说，本研究展示了一种利用废物流进行高效可持续微藻生物燃料生产的策略。
