title: High molecular weight β-poly(L-malic acid) produced by A. pullulans with Ca²⁺ added repeated batch culture.
abstract: β-Poly(malic acid) (PMLA) has attracted increasing attentions because of its potential application in medicine and other industries. In this study, the variation of PMLA molecular weight (Mw) in the batch culture and the strategies to enhance PMLA Mw were studied. Adding exogenous Ca(2+) (0.1g/L CaCl2) to the medium caused a significant increase in both PMLA concentration and Mw (11.38% and 26.3%, respectively) when Na2CO3 was used as the neutralizer. The Mw of PMLA during the process of batch culture, which associated with the specific PMLA production per unit cell mass (Yp/x) before glucose was depleted, increased from 12.522 KDa to its maximum 18.693 KDa and then kept decreasing until the end of the culture. Compared with the results in batch culture, Mw increased by 84.4% (up to 19.51 kDa) with a productivity of 1.1 gh(-1)L(-1) when the cells were maintained in exponential growth phase during Ca(2+) added repeated batch culture. The present work provides an efficient approach to obtain superior quality PMLA product with high Mw.
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Jianquan
authors.initials: J
authors.lastname: Luo
authors.affiliation: China National Center for Biotechnology Development, Beijing 100036, PR China.
authors.forename: Junxiang
authors.initials: J
authors.lastname: Yin
authors.affiliation: Department of Bioengineering, Tianjin University of Science & Technology, Tianjin 300457, PR China.
authors.forename: Changsheng
authors.initials: C
authors.lastname: Qiao
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: yhwan@ipe.ac.cn.
authors.forename: Yinhua
authors.initials: Y
authors.lastname: Wan
mesh_terms: D001203:Ascomycota / Q000737:chemistry* / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D002118:Calcium / Q000378:metabolism*; D002119:Calcium Carbonate / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005285:Fermentation; D008293:Malates / Q000737:chemistry* / Q000378:metabolism*; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D008293:Malates; D011108:Polymers; C121060:poly(malic acid); D002119:Calcium Carbonate; D002118:Calcium
keywords: Aureobasidium pullulans; Molecular weight; β-poly(l-malic acid)