Optimized medium improves expression and secretion of extremely thermostable bacterial xylanase, XynB, in Kluyveromyces lactis.
An extremely thermostable xylanase gene, xynB, from hyperthermophilic bacterium Thermotoga maritima MSB8 was successful expressed in Kluyveromyces lactis. Response surface methodology (RSM) was applied to optimize medium components for production of XynB secreted by the recombinant K. lactis. Secretion level (102 mg/L) and enzyme activity (49 U/ml) of XynB in the optimized medium (yeast extract, lactose, and urea; YLU) were much higher than those (56 mg/L, 16 U/ml) in original medium (yeast extract, lactose, and peptone; YLP). It was also observed that the secretory efficiency of mature XynB was improved by the YLU medium. mRNA levels of 13 characterized secretion-related genes between K. lactis cultured in YLP and YLU were detected using semi-quantitative RT-PCR method. It was found that unfolded protein response (UPR) related genes such as ero1, hac1, and kar2 were up-regulated in K. lactis cultured in YLU. Therefore, nutrient ingredient, especially nitrogen source had a significant influence on the XynB secretory efficiency in the host K. lactis.
State Key Laboratories for Agro-biotechnology and College of Biological Sciences, China Agricultural University, Beijing 100193, P. R. China.
Tie
T
Yin
Li-Li
LL
Miao
Fei-Fei
FF
Guan
Gui-Li
GL
Wang
Qing
Q
Peng
Bing-Xue
BX
Li
Guo-Hua
GH
Guan
Ying
Y
Li
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability; D005110:Extracellular Space / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D015966:Gene Expression Regulation, Fungal; D007716:Kluyveromyces / Q000235:genetics* / Q000378:metabolism; D021381:Protein Transport; D020124:Thermotoga maritima / Q000201:enzymology* / Q000235:genetics; D001617:beta-Glucosidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D003470:Culture Media; D001617:beta-Glucosidase; D043364:Endo-1,4-beta Xylanases; C090001:XynB xylanase