Medium optimization for the production of avermectin B1a by Streptomyces avermitilis 14-12A using response surface methodology

Gao, Hong; Liu, Mei; Liu, Jintao; Dai, Huanqin; Zhou, Xu; Li, Xiangyang; Zhuo, Ying; Zhang, Wenquan; Zhang, Lixin

doi:10.1016/j.biortech.2009.03.013

Cited by 137 publications

(79 citation statements)

References 31 publications

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“…The fitness of the model was examined by determination coefficient R 2 , which was 0.9711, indicating that the sample variation of more than 97% was attributed to the variables and that only less than 3% of the total variance could not be explained by the model. A regression model with an R 2 value higher than 0.9 could be considered as having a high correlation [35]. The adjusted determination coefficient (Adjusted R 2 = 0.9191) indicated a high degree of correlation between the observed and predicted values.…”

Section: Optimization Of Pectinase Pretreatmentmentioning

confidence: 99%

Improving Production of Bioethanol from Duckweed (Landoltia punctata) by Pectinase Pretreatment

et al. 2012

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Landoltia punctata, a widely distributed duckweed strain with the ability to accumulate starch, was used as a novel feedstock for bioethanol production by Saccharomyces cerevisiae. To improve ethanol production, pectinase pretreatment was used to release much more glucose from L. punctata mash and the pretreatment conditions (enzyme loading, temperature and pretreatment time) for the duckweed were optimized by using a surface response design. The results showed that maximum glucose yield was 218.64 ± 3.10 mg/g dry matter, which is a 142% increase compared to the untreated mash, with a pectinase dose of 26.54 pectin transeliminase unit/g mash at 45 °C for 300 min. Pectinase pretreatment apparently changed the ultrastructure of L. punctata, as evidenced by scanning electron microscopy analysis. Further fermentation experiments were performed and 30.8 ± 0.8 g/L of ethanol concentration, 90.04% of fermentation efficiency and 2.20 g/L / h of productivity rate were achieved. This is the highest ethanol concentration reported to date using duckweed as the feedstock.

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Section: Optimization Of Pectinase Pretreatmentmentioning

confidence: 99%

Improving Production of Bioethanol from Duckweed (Landoltia punctata) by Pectinase Pretreatment

et al. 2012

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“…F. bombycis can be seen as a complex nitrogen source for a high content of proteins. It was reported that complex nitrogen sources could sustain high antibiotic production, because they were supposed to be linked to the slow release of nitrogenous components during the course of fermentation (Gao et al, 2009). Figs.…”

Section: Optimization By Rsm Experimentsmentioning

confidence: 99%

Enhancing production of a 24-membered ring macrolide compound by a marine bacterium using response surface methodology

Chen

Chen³

et al. 2013

J. Zhejiang Univ. Sci. B

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A 24-membered ring macrolide compound, macrolactin A has potential applications in pharmaceuticals for its anti-infectious and antiviral activity. In this study, macrolactin A was produced by a marine bacterium, which was identified as Bacillus subtilis by 16S ribosomal RNA (rRNA) sequence analysis. Electrospray ionization mass spectrometry (ESI/MS) and nuclear magnetic resonance (NMR) spectroscopy analyses were used to characterize this compound. To improve the production, response surface methodology (RSM) involving Box-Behnken design (BBD) was employed. Faeces bombycis, the main by-product in sericulture, was used as a nitrogen source in fermentation. The interactions between three significant factors, F. bombycis, soluble starch, and (NH 4 ) 2 SO 4 were investigated. A quadratic model was constructed to fit the production and the factors. Optimum medium composition was obtained by analysis of the model. When cultivated in the optimum medium, the production of macrolactin A was increased to 851 mg/L, 2.7 times as compared to the original. This study is also useful to find another way in utilizing F. bombycis.

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“…The avermectin B1a overproducing strain of S. avermitilis 3-115 (19,20) and the wild-type strain ATCC31267 were grown in a fermentation medium. Comparative analysis of the microarray data revealed that 125 genes were differentially expressed and 31 genes were up-regulated by at least twofold at the stationary phase of 3-115 growth (Table S1).…”

Section: Resultsmentioning

confidence: 99%

Reverse biological engineering of hrdB to enhance the production of avermectins in an industrial strain of Streptomyces avermitilis

Zhuo

Zhang

Chen

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Avermectin and its analogues are produced by the actinomycete Streptomyces avermitilis and are widely used in the field of animal health, agriculture, and human health. Here we have adopted a practical approach to successfully improve avermectin production in an industrial overproducer. Transcriptional levels of the wildtype strain and industrial overproducer in production cultures were monitored using microarray analysis. The avermectin biosynthetic genes, especially the pathway-specific regulatory gene, aveR, were up-regulated in the high-producing strain. The upstream promoter region of aveR was predicted and proved to be directly recognized by σ hrdB in vitro. A mutant library of hrdB gene was constructed by error-prone PCR and selected by high-throughput screening. As a result of evolved hrdB expressed in the modified avermectin high-producing strain, 6.38 g∕L of avermectin B1a was produced with over 50% yield improvement, in which the transcription level of aveR was significantly increased. The relevant residues were identified to center in the conserved regions. Engineering of the hrdB gene can not only elicit the overexpression of aveR but also allows for simultaneous transcription of many other genes. The results indicate that manipulating the key genes revealed by reverse engineering can effectively improve the yield of the target metabolites, providing a route to optimize production in these complex regulatory systems.precision engineering | RNA polymerase | overproduction

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Medium optimization for the production of avermectin B1a by Streptomyces avermitilis 14-12A using response surface methodology

Cited by 137 publications

References 31 publications

Improving Production of Bioethanol from Duckweed (Landoltia punctata) by Pectinase Pretreatment

Improving Production of Bioethanol from Duckweed (Landoltia punctata) by Pectinase Pretreatment

Enhancing production of a 24-membered ring macrolide compound by a marine bacterium using response surface methodology

Reverse biological engineering of hrdB to enhance the production of avermectins in an industrial strain of Streptomyces avermitilis

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