Optimisation of culture conditions and development of a novel fed‐batch strategy for high production of β‐galactosidase by Kluyveromyces lactis |
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Authors: | Sheng‐ping You Xiao‐nan Wang Wei Qi Rong‐xin Su Zhi‐min He |
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Affiliation: | 1. Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China;2. State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin, China;3. Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China;4. Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin, China |
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Abstract: | The aim of this study was to enhance β‐galactosidase production by Kluyveromyces lactis CICC1773. Firstly, the optimum culture conditions were obtained by response surface methodology, and the maximum β‐galactosidase activity reached 20.6 U mL?1, about two‐fold increase than that of the initial conditions (initial fermentation medium and conditions). To further improve β‐galactosidase production, a new fed‐batch strategy based on pH feedback control was developed successfully in a 7‐L fermenter, using 400 g L?1 lactose as feeding medium. As a result, the β‐galactosidase activity and productivity reached up to 111.61 U mL?1 and 5.31 U/(mL·h), enhanced by 15.3‐fold and 17.6‐fold superior than the results of initial conditions, respectively. To our knowledge, β‐galactosidase activity obtained was the highest value among the results reported by nonrecombinant strains. These results demonstrated that the new fed‐batch strategy based on optimum culture conditions could be automatic control easily and be conductive to further scale up for industrial fermentation. |
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Keywords: | fed‐batch
Kluyveromyces lactis
pH feedback control response surface methodology β ‐galactosidase |
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