http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Wan Honggui (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
Honggui Wan,Jianfeng Yuan,Xianyang Shan,Qiyang Wu,Nan Shi 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.4
A gray and low viscosity extracellular polysaccharide (EPS) composed of N-acetylglucosamine, xylose,and mannose was isolated from culture medium of Bacillus sp. strain LBP32 by ethanol precipitation followed by dialysis and freeze-drying. The crude biopolymer showed an apparent molecular weight (Mw) of ~ 9.62 × 10^4. Chemical and spectroscopic studies revealed that the bacterial biopolymer was composed of a β-1,4-linked backbone carrying a low content of β-1,3-linked backbone. In addition, the EPS demonstrated a high antioxidant activity in a concentration dependent manner. The 50%inhibition concentration (IC_(50)) for quenching hydroxyl radical (·OH) and superoxide radical (·O_2^−) were 0.042 and 0.165 mg/mL, respectively. Furthermore, the EPS demonstrated a strong protective effect against lipid peroxidation and radiation such as UV radiation and ion beam irradiation. These results indicate that the protective effects of the EPS were most likely due to its free radical scavenging ability.
-
Chen Wang,Kai Zhang,Chen Zhongjun,Heng Cai,Wan Honggui,Ping-Kai Ouyang 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.3
Lysine decarboxylase (LDC) exhibits a significant role in cadaverine (1,5-pentanediamine, diaminopentane) production from lysine. In this study, an error-prone PCR and DNA shuffling were performed to improve the activity of LDC from Hafnia alvei AS1.1009 for cadaverine production. A sensitive high-throughput screening strategy based on a pH indicator was established for directed evolution of LDC. Several improved mutants were obtained from directed evolution and LDCV147F/E583G mutant showed highest activity to catalyze lysine to cadaverine. This mutant showed 1.62-fold high LDC activity when compared to wild-type. Further analysis by site-directed mutagenesis reveled that only the mutant E583G was sufficient for higher catalytic activity. Wild type LDC and mutant LDCE583G were purified by an improved method including hydrophobic chromatography. These purified enzymes were characterized and the kinetic parameters were compared between LDCE583G and WT LDC. Vmax of LDCE583G was 1.32-fold higher than that of WT LDC. Use of LDCE583G mutant showed 1.48-fold improved productivity of cadaverine when compared to wild type. The concentration of cadaverine in E. coli JM109/pTrc99a-ldc2-41 was 63.9 g/L with conversion yield of 93.4% during 5 h. These results indicate that the mutation has positive effects on improving LDC activity and a potential candidate for cadaverine production.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
