Improvement of astaxanthin production by a newly isolated Phaffia rhodozyma mutant with low-energy ion beam implantation

Liu, Zhi‐Qiang; Zhang, J.-F.; Zheng, Yu‐Guo; Shen, Yin‐Chu

doi:10.1111/j.1365-2672.2007.03603.x

Cited by 53 publications

(22 citation statements)

References 48 publications

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“…Because the ITS region is highly conserved intraspecifically, it is variable between different species. ITS region polymorphism is often used in taxonomy; but now, it is being well recognized for identifying fungi species [26]. In this study, we combined the morphological and physiological method with DNA sequence analysis method to identify the genetic position of the isolated strain producing xylanase.…”

Section: Discussionmentioning

confidence: 99%

Isolation and Identification of a Newly Isolated Alternaria sp. ND-16 and Characterization of Xylanase

Liu

Cui

et al. 2008

Appl Biochem Biotechnol

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Alternaria sp. ND-16, a bacterium isolated from soil sample, was identified as a strain of Alternaria mali based on the morphology and comparison of internal transcribed spacer rDNA gene sequence studies. Furthermore, it is demonstrated that this strain has xylanase activity, and the activity can be optimized under suitable growing conditions where wheat bran and urea are the primary sources of carbon and nitrogen. Partially purified xylanase from Alternaria sp. ND-16 is shown to have an optimal pH of 6.0 and optimal temperature of 50 degrees C, making this enzyme potentially suitable for industrial applications. It is also demonstrated that Na(+) and Mn(2+) show strong inhibition of the xylanase while K(+), Li(+), Fe(2+), Cu(2+), and Zn(2+) have no significant effect on the activity.

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Section: Discussionmentioning

confidence: 99%

Isolation and Identification of a Newly Isolated Alternaria sp. ND-16 and Characterization of Xylanase

Liu

Cui

et al. 2008

Appl Biochem Biotechnol

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“…The mutants with high activity were selected for mutation by low energy N ? ion beams (IB) [9]. The ion implantation system used in the present study has been previously described [22].…”

Section: Mutagenesismentioning

confidence: 99%

Enantioselective biocatalytic hydrolysis of (R,S)-mandelonitrile for production of (R)-(−)-mandelic acid by a newly isolated mutant strain

Xue

Liu

et al. 2010

J Ind Microbiol Biotechnol

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(R)-(-)-Mandelic acid (R-MA) is an important intermediate with broad uses. Recently, R-MA production using nitrilase has been gaining more and more attention due to its higher productivity and enantioselectivity. In this work, a new bacterium WT10, which exhibited favorable nitrilase activity and excellent enantioselectivity for production of R-MA by enantioselective biocatalytic hydrolysis of (R,S)-mandelonitrile, was isolated and identified as a strain of Alcaligenes faecalis. In order to improve its nitrilase activity for industrial application, the wild-type strain WT10 was further subjected to mutagenesis using a combined LiCl-ultraviolet irradiation and low energy N(+) ion beams implantation technique. A valuable mutant strain A. faecalis ZJUTB10 was obtained. The nitrilase specific activity of the mutant strain was greatly improved up to 350.8 U g(-1), in comparison with wild-type strain WT10 of 53.09 U g(-1). The reaction conditions for R-MA production by mutant strain A. faecalis ZJUTB10 were also optimized. Nitrilase activity in mutant strain showed a broad pH optimum at pH 7.7-8.5. The optimal temperature was 35°C. The highest production rate reached 9.3 mmol h(-1) g(-1). The results showed that mutant strain A. faecalis ZJUTB10 was a new candidate for efficient R-MA production from (R,S)-mandelonitrile and could potentially be used in industrial production.

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“…The strain M. neoaurum ZJUVN was isolated using gradient dilution of 13 ions/cm 2 . The mutation of the strain was carried out as described by Liu et al (2007). After ion implantation treatment, samples were diluted by physiological sodium chloride solution, and then placed onto seed medium plates containing 1.0 g/L PS.…”

Section: Microorganismsmentioning

confidence: 99%

Optimization of biotransformation from phytosterol to androstenedione by a mutant Mycobacterium neoaurum ZJUVN-08

Zhang

Peng

et al. 2013

J. Zhejiang Univ. Sci. B

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Biotransformation of phytosterol (PS) by a newly isolated mutant Mycobacterium neoaurum ZJUVN-08 to produce androstenedione has been investigated in this paper. The parameters of the biotransformation process were optimized using fractional factorial design and response surface methodology. Androstenedione was the sole product in the fermentation broth catalyzed by the mutant M. neoaurum ZJUVN-08 strain. Results showed that molar ratio of hydroxypropyl-β-cyclodextrin (HP-β-CD) to PS and substrate concentrations were the two most significant factors affecting androstenedione production. By analyzing the statistical model of three-dimensional surface plot, the optimal process conditions were observed at 0.1 g/L inducer, pH 7.0, molar ratio of HP-β-CD to PS 1.92:1, 8.98 g/L PS, and at 120 h of incubation time. Under these conditions, the maximum androstenedione yield was 5.96 g/L and nearly the same with the non-optimized (5.99 g/L), while the maximum PS conversion rate was 94.69% which increased by 10.66% compared with the non-optimized (84.03%). The predicted optimum conditions from the mathematical model were in agreement with the verification experimental results. It is considered that response surface methodology was a powerful and efficient method to optimize the parameters of PS biotransformation process.

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Improvement of astaxanthin production by a newly isolated Phaffia rhodozyma mutant with low-energy ion beam implantation

Cited by 53 publications

References 48 publications

Isolation and Identification of a Newly Isolated Alternaria sp. ND-16 and Characterization of Xylanase

Isolation and Identification of a Newly Isolated Alternaria sp. ND-16 and Characterization of Xylanase

Enantioselective biocatalytic hydrolysis of (R,S)-mandelonitrile for production of (R)-(−)-mandelic acid by a newly isolated mutant strain

Optimization of biotransformation from phytosterol to androstenedione by a mutant Mycobacterium neoaurum ZJUVN-08

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