Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, 211004, U.P., India; Department of Biotechnology, AKS University Satna, 485001, M.P., India.
Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, 211004, U.P., India.
J Environ Manage. 2023 Apr 15;332:117350. doi: 10.1016/j.jenvman.2023.117350. Epub 2023 Jan 24.
In this study, an airlift reactor (ALR) has been employed to evaluate the carbon dioxide fixation rate (Rc) and lipid yield (LY) of unicellular green microalgae Scenedesmus sp. ASK22, using dairy effluent as a biofuel feedstock. Independent process parameters (PPs) such as light intensity, CO concentration, and aeration rate and their effect on R and LY were revealed. The central composite design (CCD) was used to optimize the PPs. The best-operating conditions were measured as light intensity -6.24 Klux, CO concentration -14.03% (v v), and aeration rate -1.02 liter per minute (LPM). Under these conditions, LY and Rc were found to be 4.22 gL and 1.27 gLd which were 2.24- and 1.94-fold higher than the value obtained in the control experiment (1.88 gL and 0.656 gLd) at the end of 12th day. The corresponding values for bioremediation of nitrate, phosphate, as well as chemical oxygen demand (COD), remained within 98-100%. The biochemical, CHN, thermogravimetric, and fatty acid analysis of Scenedesmus sp. ASK22 biomass and lipid confirmed their potential as a clean biofuel feedstock. Furthermore, a comprehensive analysis of lipid-extracted microalgae biomass (LEMB) was carried out suggesting that LEMB could be used as a high-quality cattle and fish feed, fertilizers, and a sustainable source for biogas, bioethanol, and bio-oils. In addition to improving the developed system's efficiency, a semi-continuous regime was implemented which resulted in biomass productivity of 1.89 gLd which was 2.6-fold higher than the batch cultivation without hampering lipid productivity (0.377 gLd). The present results suggest that Scenedesmus sp. ASK22 is a potential candidate for CO sequestration from atmosphere/flue gas, biofuel production (biodiesel, bioethanol, biogas, biobutanol, etc.), and waste remediation.
在这项研究中，采用气升式反应器 (ALR) 评估了单细胞绿微藻 Scenedesmus sp. ASK22 的二氧化碳固定率 (Rc) 和脂质产率 (LY)，使用乳制品废水作为生物燃料原料。揭示了独立的工艺参数 (PP)，如光照强度、CO 浓度和充气率及其对 R 和 LY 的影响。采用中心复合设计 (CCD) 对 PP 进行了优化。最佳操作条件测量为光照强度 -6.24 Klux、CO 浓度 -14.03%（v/v）和充气率 1.02 升/分钟 (LPM)。在这些条件下，第 12 天结束时，LY 和 Rc 分别为 4.22 g/L 和 1.27 g/L/d，分别比对照实验（第 12 天结束时 1.88 g/L 和 0.656 g/L/d）高 2.24-1.94 倍。硝酸盐、磷酸盐以及化学需氧量 (COD) 的生物修复率保持在 98-100%之间。Scenedesmus sp. ASK22 生物质和脂质的生化、CHN、热重和脂肪酸分析证实了它们作为清洁生物燃料原料的潜力。此外，对提取脂质的微藻生物质 (LEMB) 进行了全面分析，表明 LEMB 可用作高质量的牛和鱼饲料、肥料以及沼气、生物乙醇和生物油的可持续来源。除了提高开发系统的效率外，还实施了半连续制，生物量生产力为 1.89 g/L/d，比没有阻碍脂质生产力（0.377 g/L/d）的分批培养高 2.6 倍。目前的结果表明，Scenedesmus sp. ASK22 是从大气/烟道气中捕获 CO、生产生物燃料（生物柴油、生物乙醇、沼气、生物丁醇等）和废物修复的潜在候选物。
