Improved performance of cross-flow ultrafiltration for the recovery and purification of Ca²⁺ conditioned lipopeptides in diafiltration mode of operation

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• 作者：Vivek Rangarajan ; Gunaseelan Dhanarajan ; Ramkrishna Sen
• 关键词：Cross-flow ultrafiltration (CFUF) ; Lipopeptides ; Ca2+ induced micelle stabilization ; Improved recovery and purification ; DLS analysis
• 刊名：Journal of Membrane Science
• 出版年：15 March, 2014
• 年：2014
• 卷：454
• 期：Complete
• 页码：436-443
• 全文大小：705 K

文摘

This is for the first time that an attempt was made to enhance the performance of cross-flow ultrafiltration (CFUF) for the recovery and purification of lipopeptides by size-conditioning their micelles with Ca²⁺ ions and operating the system in diafiltration mode. In this study, polyether sulfone (PES) membranes with MWCOs 10, 30 and 50 kDa were evaluated for recovery and purification of lipopeptides produced by Bacillus sp. CFUF studies performed under batch mode showed poor recovery (68卤2%) of F₂ fraction comprising Fengycin isoforms, whereas F₁ fraction comprising a mixture of surfactin and iturin isoforms showed a moderate recovery of 83.5卤2.4% in 50 kDa MWCO membrane. To improve the recovery, lipopeptides were conditioned with Ca²⁺ ions. The CFUF purification of this size-conditioned lipopeptide solution under diafiltration mode was carried out in 50 kDa PES membrane. Continuous irrigation of Ca²⁺ to lipopeptide solution under diafiltration mode of CFUF resulted in the increased recovery of lipopeptides, F₁ (surfactin+iturin) fraction about 90.5卤2.1% and F₂ about 95.3卤2.0%. Further, the colored impurities with MW range of 2334-3506 Da were effectively removed from the solution. The results of CFUF purification of Ca²⁺conditioned lipopeptide solution under diafiltration mode indicate that this process can be readily scaled up to the commercial level, workable even with higher MWCO membranes.