BIOCATALYSIS AND BIOTRANSFORMATION
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2016
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IF 0.892
Xiao-Ying Bie,Ming-Jun Zhu
The effects of important production variables on the biotransformation of sucrose by immobilized cells of Phaffia rhodozyma were investigated. Cell concentration had negative effect on the maximum concentration of neokestose and the optimal concentration was 16 g/l (calculated by dry weight). The concentration of sucrose had a positive effect on the maximum concentration of neokestose within 1.170 mol/l. Elevating the reaction temperature increased the reaction rate but decreased the maximum concentration of neokestose. Sugar cane juice could be used as an inexpensive substrate for neokestose production. Additionally, a 30-d continuous neokestose production was found feasible in a packed bed reactor, indicating that the cell immobilization with chitosan-coated alginate has the potential for industrial production.
研究领域:
工业微生物学
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生物工程
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产品关联
DOI
高影响因子
Frontiers in Microbiology
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2022
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IF 6.064
Shi Zhihui,He Xiaoxian,Zhang Hailiang,Guo Xuena,Cheng Yanfei,Liu Xuelian,Wang Zhaoyue,He Xiuping
Carotenoids are unsaturated compounds with terpene groups. Among them, astaxanthin has strong antioxidant properties. It is widely used in aquaculture, food, medicine, and cosmetics with a broad market prospect. Phaffia rhodozyma is an important microorganism that synthesizes astaxanthin, but its wild strains have low pigment content, long growth cycle, and low fermentation temperature. Therefore, it is important to research the genetic improvement of the physiological and biochemical properties of P. rhodozyma. In this study, the atmospheric and room temperature plasma mutagenesis technology was adopted, through the functional evolution of the carotenoid production performance; then, through the comparative analysis of the genomics and transcriptomics of the wild strain and evolved strain, the key factor GST1 gene that affects carotenoid synthesis was discovered.
研究领域:
微生物学
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遗传学
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生物化学
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DOI
PubMed
高影响因子
Frontiers in Microbiology
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2024
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IF 4
Jia Jianping,Chen Zhitao,Li Qingqing,Li Feifei,Liu Siru,Bao Guoliang
Astaxanthin has multiple physiological functions and is applied widely. The yeast Phaffia rhodozyma is an ideal source of microbial astaxanthin. However, the stress conditions beneficial for astaxanthin synthesis often inhibit cell growth, leading to low productivity of astaxanthin in this yeast. In this study, 1 mg/L melatonin (MT) could increase the biomass, astaxanthin content, and yield in P. rhodozyma by 21.9, 93.9, and 139.1%, reaching 6.9 g/L, 0.3 mg/g DCW, and 2.2 mg/L, respectively. An RNA-seq-based transcriptomic analysis showed that MT could disturb the transcriptomic profile of P. rhodozyma cell. Furthermore, differentially expressed gene (DEG) analysis show that the genes induced or inhibited significantly by MT were mainly involved in astaxanthin synthesis, metabolite metabolism, substrate transportation, anti-stress, signal transduction, and transcription factor. A mechanism of MT regulating astaxanthin synthesis was proposed in this study. The mechanism is that MT entering the cell interacts with components of various signaling pathways or directly regulates their transcription levels. The altered signals are then transmitted to the transcription factors, which can regulate the expressions of a series of downstream genes as the DEGs. A zinc finger transcription factor gene (ZFTF), one of the most upregulated DEGs, induced by MT was selected to be overexpressed in P. rhodozyma. It was found that the biomass and astaxanthin synthesis of the transformant were further increased compared with those in MT-treatment condition. Combining MT-treatment and ZFTF overexpression in P. rhodozyma, the biomass, astaxanthin content, and yield were 8.6 g/L, 0.6 mg/g DCW, and 4.8 mg/L and increased by 52.1, 233.3, and 399.7% than those in the WT strain under MT-free condition. In this study, the synthesis and regulation theory of astaxanthin is deepened, and an efficient dual strategy for industrial production of microbial astaxanthin is proposed.
研究领域:
微生物学
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生物化学
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基因工程
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产品关联
DOI
PubMed
高影响因子
Frontiers in Bioengineering and Biotechnology
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2023
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IF 5.7
Jianping Jia,Feifei Li,Yifei Luan,Siru Liu,Zhitao Chen,Guoliang Bao
Phaffia rhodozyma represents an excellent microbial resource for astaxanthin production. However, the yeast’s low astaxanthin productivity poses challenges in scaling up industrial production. Although P . rhodozyma originates from plant material, and phytohormones have demonstrated their effectiveness in stimulating microbial production, there has been limited research on the effects and mechanisms of phytohormones on astaxanthin biosynthesis in P . rhodozyma . In this study, the addition of exogenous salicylic acid (SA) at a concentration as low as 0.5 mg/L significantly enhanced biomass, astaxanthin content, and yield by 20.8%, 95.8% and 135.3% in P . rhodozyma , respectively. Moreover, transcriptomic analysis showed that SA had discernible impact on the gene expression profile of P. rhodozyma cells. Differentially expressed genes (DEGs) in P. rhodozyma cells between the SA-treated and SA-free groups were identified. These genes played crucial roles in various aspects of astaxanthin and its competitive metabolites synthesis, material supply, biomolecule metabolite and transportation, anti-stress response, and global signal transductions. This study proposes a regulatory mechanism for astaxanthin synthesis induced by SA, encompassing the perception and transduction of SA signal, transcription factor-mediated gene expression regulation, and cellular stress responses to SA. Notably, the polyamine transporter gene (PT), identified as an upregulated DEG, was overexpressed in P. rhodozyma to obtain the transformant Prh-PT-006. The biomass, astaxanthin content and yield in this engineered strain could reach 6.6 g/L, 0.35 mg/g DCW and 2.3 mg/L, 24.5%, 143.1% and 199.0% higher than the wild strain at the SA-free condition, respectively. These findings provide valuable insights into potential targets for genetic engineering aimed at achieving high astaxanthin yields, and such advancements hold promise for expediting the industrialization of microbial astaxanthin production.
研究领域:
微生物学
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生物技术
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分子生物学
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遗传工程
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DOI
PubMed
高影响因子
MOLECULES
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2024
·Vol. 29
·期 17
·4201
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IF 4.2
Wenxuan Jiang,Xiangrong Deng,Lanxian Qin,Dahai Jiang,Mengqi Lu,Kai Chen,Manqi Yang,Liangliang Zhang,Jianchun Jiang,Liming Lu
This study focused on developing an effective cell wall-breaking method forPhaffia rhodozyma, followed by utilizing subcritical fluid extraction to isolate, extract, and concentrate astaxanthin from the complex fermentation products ofP. rhodozyma. A comprehensive comparison of seven distinct methods for disrupting cell walls, including dimethyl sulfoxide treatment, lactic acid treatment, sodium hydroxide treatment,β-glucanase enzymatic digestion,β-mannanase enzymatic digestion, and a combined enzymatic treatment involving bothβ-mannanase andβ-glucanase was conducted. The results identified the lactic acid method as the most effective in disrupting the cell walls ofP. rhodozyma. The software, Design Expert, was used in the process of extracting astaxanthin from cell lysates using a subcritical extraction method. Through fitting analysis and response surface optimization analysis by Design Expert, the optimal extraction conditions were determined as follows: an extraction temperature of 41 °C, extraction frequency of two times, and extraction time of 46 min. These parameters facilitated the efficient extraction, concentration, and enrichment of astaxanthin fromP. rhodozyma, resulting in an astaxanthin concentration of 540.00 mg/L. This result can establish the foundation for its high-value applications.
研究领域:
生物技术
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食品科学
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产品关联
DOI
PubMed
高影响因子
Frontiers in Microbiology
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2025
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IF 4.5
Jianping Jia,Chenxi Ye,Sainan Jin,Qingqing Li,Zhengyi Pan,Wen Wen,Guoliang Bao
Astaxanthin is a strong antioxidant and is widely applied in food industry. The yeast Phaffia rhodozyma is an ideal microbial astaxanthin resource. However, the nitrogen-deficiency stress, which is beneficial for astaxanthin synthesis, often impairs cell growth, leading to low productivity. In this study, an imbalance between cellular growth and astaxanthin synthesis in P. rhodozyma under nitrogen-deficient (H) and nitrogen-sufficient (L) conditions was identified. A comparative RNA-seq transcriptome analysis between the H and L groups revealed well-discriminated patterns. The differentially expressed genes (DEGs) indicated that the regulation of nitrogen deficiency does not occur directly in the astaxanthin biosynthesis pathway but rather operates at the global cellular level, involving processes such as central and energy metabolism, antioxidative stress responses, signal transduction, competitive metabolic pathways, and material transportation. Based on these findings, a regulatory mechanism is proposed, which involves cellular sensing of nitrogen sources in the medium, alterations in signaling pathways that direct effectors, and the regulation of multiple downstream target genes through post-translational modifications, protein interactions, gene transcription, and the protein and metabolite levels. Six DEGs were overexpressed in the wild strain (WT) of Phaffia rhodozyma, and the mutants M2 and M6, expressing the NHEJ gene for DNA repair and the ferric reductase gene, showed higher biomass and astaxanthin content compared with the WT strain under nitrogen-deficient conditions. However, the remaining mutants exhibited unchanged or even reduced biomass and astaxanthin productivity. Subsequently, a co-expression mutant (M7) carrying the two DEGs was constructed. This mutant exhibited further increases in both biomass and astaxanthin content, with 61.5 and 133.3% higher yields than the WT strain, respectively, and a 265.8% increase in final astaxanthin production.
研究领域:
微生物学
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分子生物学
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代谢工程
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合成生物学
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工业生物技术
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产品关联
DOI
PubMed
高影响因子
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