School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China.
School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China.
J Biosci Bioeng. 2014 Jul;118(1):29-33. doi: 10.1016/j.jbiosc.2013.12.021. Epub 2014 Feb 4.
High cost of biomass recovery is one of the bottlenecks for developing cost-effective processes with microalgae, particularly for the production of biofuels and bio-based chemicals through biorefinery, and microalgal biomass recovery through cell flocculation is a promising strategy. Some microalgae are naturally flocculated whose cells can be harvested by simple sedimentation. However, studies on the flocculating agents synthesized by microalgae cells are still very limited. In this work, the cell flocculation of a spontaneously flocculating microalga Chlorella vulgaris JSC-7 was studied, and the flocculating agent was identified to be cell wall polysaccharides whose crude extract supplemented at low dosage of 0.5 mg/L initiated the more than 80% flocculating rate of freely suspended microalgae C. vulgaris CNW11 and Scenedesmus obliquus FSP. Fourier transform infrared (FTIR) analysis revealed a characteristic absorption band at 1238 cm(-1), which might arise from PO asymmetric stretching vibration of [Formula: see text] phosphodiester. The unique cell wall-associated polysaccharide with molecular weight of 9.86×10(3) g/mol, and the monomers consist of glucose, mannose and galactose with a molecular ratio of 5:5:2. This is the first time to our knowledge that the flocculating agent from C. vulgaris has been characterized, which could provide basis for understanding the cell flocculation of microalgae and breeding of novel flocculating microalgae for cost-effective biomass harvest.
高生物质回收成本是开发具有成本效益的微藻工艺的瓶颈之一，特别是通过生物炼制生产生物燃料和生物基化学品，以及通过细胞絮凝回收微藻生物质，这是一种很有前途的策略。有些微藻自然絮凝，其细胞可以通过简单的沉降收获。然而，关于微藻细胞合成的絮凝剂的研究仍然非常有限。在这项工作中，研究了一种自发絮凝的微藻普通小球藻 JSC-7 的细胞絮凝作用，并鉴定出絮凝剂是细胞壁多糖，其粗提取物在低剂量 0.5mg/L 下补充，可引发超过 80%自由悬浮的微藻 C. vulgaris CNW11 和斜生栅藻 FSP 的絮凝率。傅里叶变换红外（FTIR）分析显示在 1238cm(-1)处有一个特征吸收带，可能源于[Formula: see text]磷酸二酯的 PO 不对称伸缩振动。这种独特的与细胞壁相关的多糖的分子量为 9.86×10(3)g/mol，其单体由葡萄糖、甘露糖和半乳糖组成，摩尔比为 5:5:2。据我们所知，这是首次对普通小球藻的絮凝剂进行了表征，这可为理解微藻的细胞絮凝作用和新型絮凝微藻的选育以实现经济高效的生物质收获提供依据。
