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- 저자 : Lingqia Su (검색결과 4 건)
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Jie He,Lingqia Su,Xiaojun Sun,Jiajia Fu,Jian Chen,Jing Wu 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.1
A xylanase (XynA) was purified from the culturemedium of Streptomyces sp. FA1, which was previouslyisolated from a bamboo retting system. XynA had amolecular mass of 43 kDa, displayed maximal activity atpH 5.5, retained 41% of its maximal activity at pH 11.0,and was stable over a wide pH range (3.0 ~ 11.0). PurifiedXynA was subjected to peptide mass fingerprinting, whichled to the cloning of the xynA gene. The xynA gene, whichencodes a mature protein of 436 amino acids, washeterologously expressed in E. coli BL21(DE3). The activityin the culture medium could reach 213.5 U/mL, which was11.2-fold higher than that produced by Streptomyces sp. FA1. BLAST searching revealed that full-length XynAshares less than 90% identity with most of its homologues,whereas amino acids 48-436 of the enzyme share 97%identity with an open reading frame encoding a putativefull-length mature xylanase from Streptomyces tendae. Thetruncated xynA gene, xynA48-436, was cloned and expressedin E. coli, however, no xylanase activity could be detectedin the culture medium. Based on these results, it is suggestedthat XynA is a new member of glycoside hydrolasesfamily10 with exceptional catalytic efficiency at alkalinepH.
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Bin Li,Lei Wang,Lingqia Su,Sheng Chen,Zhaofeng Li,Jian Chen,Jing Wu 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.6
OmpA signal peptide mediated cgt gene from Paenibacillus macerans JFB05-01 was cloned and expressed in E. coli BL21 (DE3). The effects of glycine and Triton X-100 on extracellular production of α-cyclodextrin glycosyltransferase (α-CGTase) were investigated. When supplemented with Gly or Triton X-100 to the culture media individually, the secreted extracellular enzyme reached 32or 33 U/mL at 48 h of cultivation, respectively. When supplemented with Gly and Triton X-100 together, the extracellular α-CGTase activity reached 48 U/mL after 48 h cultivation, which was 20-fold of the control group without any additives. Analysis of membrane permeability demonstrated that addition of glycine and Triton X-100enhanced the permeability of both outer and inner membrane. The potential mechanism of the enhanced protein secretion was discussed.
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Yingchun Guo,Sheng Chen,Lingqia Su,Jing Wu,Jian Chen 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.6
Polyamidase was able to hydrolyze the amidebond of insoluble polymer. In the present study, apolyamidase from Nocardia farcinica CGMCCC4.1166was cloned and expressed in E. coli BL21(DE3). Therecombinant polyamidase was purified to homogeneity,through a combination of chromatography of anion exchange,and hydrophobic interaction. The purified enzyme wascharacterized in detail. The optimum temperature of theenzyme was 50°C, and it was stable below 40°C. Theenzyme had an optimum pH of 8.0, with pH stabilitybetween pH 7.0 and 9.0. The enzyme does not need metalion as cofactor. In addition, when the enzyme was utilizedto hydrolyze polyamide, the monomeric product of adipicacid was verified by HPLC analysis; as well, the wettabilityand dyeability of polyamide fabric after enzyme treatmentwere significantly improved, which differed from those ofits inactive S173A mutant, and the amidase from Rhodococcuspyridinivorans. Furthermore, the structural featuresnear the active site of polyamidase, different from otheramidases, were explored.
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( Kang Zhang ),( Ruiting Tan ),( Dongbang Yao ),( Lingqia Su ),( Yongmei Xia ),( Jing Wu ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.4
Pyrococcus furiosus α-amylase can hydrolyze α-1,4 linkages in starch and related carbohydrates under hyperthermophilic condition (~ 100°C), showing great potential in a wide range of industrial applications, while its relatively low productivity from heterologous hosts has limited the industrial applications. Bacillus subtilis, a gram-positive bacterium, has been widely used in industrial production for its non-pathogenic and powerful secretory characteristics. This study was conducted to increase production of P. furiosus α-amylase in B. subtilis through three strategies. Initial experiments showed that co-expression of P. furiosus molecular chaperone peptidyl-prolyl cis-trans isomerase through genomic integration mode, using a CRISPR/Cas9 system, increased soluble amylase production. Therefore, considering that native P. furiosus α-amylase is produced within a hyperthermophilic environment and is highly thermostable, heat treatment of intact culture at 90℃ for 15 min was performed, thereby greatly increasing soluble amylase production. After optimization of the culture conditions (nitrogen source, carbon source, metal ion, temperature and pH), experiments in a 3-L fermenter yielded a soluble activity of 3,806.7 U/ml, which was 3.3- and 28.2-fold those of a control without heat treatment (1,155.1 U/ml) and an empty expression vector control (135.1 U/ml), respectively. This represents the highest P. furiosus α-amylase production reported to date and should promote innovation in the starch liquefaction process and related industrial productions. Meanwhile, heat treatment, which may promote folding of aggregated P. furiosus α-amylase into a soluble, active form through the transfer of kinetic energy, may be of general benefit when producing proteins from thermophilic archaea.
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