Fermentative production of l-galactonate by using recombinant Saccharomyces cerevisiae containing the endogenous galacturonate reductase gene from Cryptococcus diffluens

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• 作者：Takeo Matsubara ; Shohei Hamada ; Ayaka Wakabayashi ; Masao Kishida ; ^{masyksd@biochem.osakafu-u.ac.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：d-Galacturonate ; l-Galactonate ; Cryptococcus diffluens ; Saccharomyces cerevisiae ; Galacturonate reductase
• 刊名：Journal of Bioscience and Bioengineering
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：122
• 期：5
• 页码：639-644
• 全文大小：533 K

文摘

The GAR1 gene, encoding d-galacturonate reductase in Cryptococcus diffluens, was isolated, and the GAR1-expression plasmid was constructed by insertion of GAR1 downstream of the yeast constitutive promoter in the yeast-integrating vector. Recombinant Saccharomyces cerevisiae expressing C. diffluensd-galacturonate reductase from a genome integrated copy of the gene was cultured for use the conversion of d-galacturonic acid to l-galactonic acid. The optimum conditions for l-galactonic acid production were determined in terms of the initial concentration of d-galacturonic acid, fermentation pH, and mixed sugars. The following conditions yielded high efficiency in the conversion of d-galacturonic acid to l-galactonic acid in large-scale cultures: 0.1% initial d-galacturonic acid concentration, pH 3.5, and glucose as additional sugar. The aerobic condition was necessary for the conversion of d-galacturonic acid. Subculture of that recombinant was not showing to decrease of the d-galacturonic acid conversion rate even though it was repeated in ten generations. Culturing in scale-up, the conversion rate of d-galacturonic acid to l-galactonic acid was increased.