Goswami Gargi, Kumar Ratan, Sinha Ankan, Maiti Soumen Kumar, Chandra Dutta Babul, Singh Harendra, Das Debasish
Department of Biosciences & Bioengineering, Indian Institute of Technology Guwahati Assam 781039 India
Institute of Biotechnology & Geotectonic Studies, ONGC Ltd A&AA Basin, Cinnamara Jorhat Assam 785704 India.
RSC Adv. 2019 Nov 28;9(67):39011-39024. doi: 10.1039/c9ra08072d. eCollection 2019 Nov 27.
A low-cost and scalable harvesting process was demonstrated for sp. FC2 IITG, which offered an improved process economy for the production of a microalgal biomass feedstock (i) the utilization of a cheaper commercial grade chemical flocculant; (ii) the recycling of post-harvested nutrient-rich spent water for the successive growth of the FC2 cells and (iii) the modulation of the flocculant dose, resulting in the non-requirement of a pH adjustment of the spent water and separate inoculum development step. Ferrous sulphate and ferric chloride were screened from a pool of four commercial grade flocculants, resulting in high harvesting efficiencies of 99.83% and 99.93% at the lower flocculant doses (g of flocculant g of dry biomass) of 2.5 and 3, respectively. The effect of the recycled nutrient-rich spent water and treated non-flocculated microalgal cells after harvesting was evaluated for the growth performance of the FC2 cells in six successive batches. It was found that ferrous sulphate was superior over ferric chloride in terms of the recyclability of the spent water for more number of batches, offering similar growth kinetics and nutrient recovery efficiency as compared with that of the control sample. The scale-up feasibility of the harvesting process was evaluated with a 5 L photobioreactor under indoor conditions and a 350 L open raceway pond under outdoor conditions with a modulated flocculant dose of 1.5 g ferrous sulphate. g dry biomass. The harvesting cost of 1 kg biomass using commercial grade ferrous sulphate was estimated to be in the range of 0.17-0.3 USD and was significantly lower as compared to that of analytical grade ferrous sulphate.
已证明一种低成本且可扩展的采收工艺适用于sp. FC2 IITG，该工艺为微藻生物质原料的生产提供了更高的工艺经济性：(i) 使用更便宜的商业级化学絮凝剂；(ii) 将收获后富含营养的废水循环用于FC2细胞的连续生长；(iii) 调节絮凝剂剂量，从而无需对废水进行pH调节以及单独的接种物培养步骤。从四种商业级絮凝剂中筛选出硫酸亚铁和氯化铁，在较低的絮凝剂剂量（絮凝剂克数/干生物质克数）分别为2.5和3时，收获效率高达99.83%和99.93%。评估了循环利用的富含营养的废水以及收获后经处理的未絮凝微藻细胞对FC2细胞在六个连续批次中的生长性能的影响。结果发现，就废水可循环使用的批次数量而言，硫酸亚铁优于氯化铁，与对照样品相比，其生长动力学和营养回收效率相似。在室内条件下使用5 L光生物反应器以及在室外条件下使用350 L开放式跑道池塘，并将絮凝剂剂量调节为1.5 g硫酸亚铁/干生物质克数，对采收工艺的放大可行性进行了评估。使用商业级硫酸亚铁收获1 kg生物质的成本估计在0.17 - 0.3美元范围内，与分析级硫酸亚铁相比显著更低。
