Evaluation of enhancing effect of soybean oil on polymalic acid production by Aureobasidium pullulans HA-4D
Jun Xia1, Sili Liu1, Jiali Jiao1
1Jiangsu Key Laboratory for Biomass-Based Energy and Enzyme Technology, Jiangsu Collaborative Innovation Center of Regional Modern Agriculture and Environmental Protection, College of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai'an, 223300, China.
Abstract:
Polymalic acid (PMA) is a water-soluble polyester produced by Aureobasidium pullulans. In this study, the physiological response of A. pullulans after the addition of vegetable oils was investigated. Soybean oil (SBO) is pivotal for shortening fermentation time and achieving high PMA titer. With the addition of 1% (w/v) SBO, the titer and productivity of PMA was, respectively, increased by 34.2% and 80%. SBO acted as a chemical stimulatory agent rather than a carbon source, the enhancement on PMA production was attributed to the component of fatty acid. SBO induced the dimorphism (yeast-like cells and mycelia) of A. pullulans, in vitro enzyme activities indicated that the TCA oxidative branch for malic acid synthesis might be strengthened, which could generate more ATP for PMA synthesis, and the assay of intracellular energy supply validated this deduction. This study provided a new sight for recognizing the regulatory behavior of SBO in A. pullulans.
Insights
Soybean oil (SBO) enhances polymalic acid (PMA) production in Aureobasidium pullulans by stimulating fatty acid components. This leads to increased PMA titer and productivity, offering new insights into microbial fermentation regulation.
Area of Science:
- Biotechnology
- Microbial Physiology
- Polymer Science
Background:
- Polymalic acid (PMA) is a valuable water-soluble polyester synthesized by the fungus Aureobasidium pullulans.
- Optimizing PMA production is crucial for its industrial applications.
- Understanding the factors influencing PMA biosynthesis in A. pullulans is essential for yield improvement.
Purpose of the Study:
- To investigate the physiological effects of vegetable oils, specifically soybean oil (SBO), on PMA production by A. pullulans.
- To elucidate the mechanism by which SBO enhances PMA yield and productivity.
- To explore the role of SBO in regulating A. pullulans morphology and metabolism.
Main Methods:
- Cultivation of A. pullulans with varying concentrations of SBO.
- Measurement of PMA titer and productivity.
- Analysis of A. pullulans cell morphology (dimorphism).
- In vitro enzyme activity assays related to malic acid synthesis.
- Assay of intracellular energy supply (ATP levels).
Main Results:
- Addition of 1% (w/v) SBO significantly increased PMA titer by 34.2% and productivity by 80%.
- SBO acted as a chemical stimulant, with fatty acids identified as the key enhancing components.
- SBO induced dimorphism in A. pullulans (yeast-like cells and mycelia).
- Enzyme assays and energy supply measurements indicated strengthened TCA oxidative pathways, leading to increased ATP for PMA synthesis.
Conclusions:
- Soybean oil is an effective stimulatory agent for enhancing polymalic acid production in Aureobasidium pullulans.
- The mechanism involves SBO-induced dimorphism, enhanced TCA cycle activity, and increased intracellular ATP levels.
- Fatty acids within SBO are crucial for boosting PMA yield, offering a novel strategy for microbial fermentation optimization.
