| Abstrakt: |
Surfactants are used in many industries such as agriculture, petrochemicals, and bioremediation. Developing using greener products leads to garnering more attention to biosurfactants. The advantages of biosurfactants compared with chemical surfactants are proper biodegradability, less toxicity, environmentally friendly, and higher efficiency. However, high production costs and low yields are important problems in the economic production of biosurfactants. As a result, optimizing and increasing the production of biosurfactants are of great importance. In this study, continuous chemostat fermentation was used to raise process time, control the process parameters, and increase the efficiency of rhamnolipid biosurfactant by Pseudomonas aeruginosa HK02. First, the best carbon source, the concentration of the minerals in the feed, and the process parameters were determined. Then, experiments were done at different flow rates to determine the washout and optimal flow rate with high yield. The best source of carbon for this strain was sunflower and soybean oil. KS 6.63 (g/L) and μmax 0.0377 (1/h) were obtained. The flow rate of 240 mL/day with a yield(p/s) of 0.88 (g/g) had the highest efficiency. The process was tested at a flow rate of 240 mL/day for 30 days. The washout flow rate was 600 mL/day. The biosurfactant production reaches 200 g/L at optimum condition. The produced biosurfactant was able to reduce the surface tension of water to 31 mN/m at 450 ppm. The results showed that the continuous fermentation process was more economical and suitable for large-scale production of rhamnolipid biosurfactants, because of high productivity, and the possibility of continuing the process for one month and more. [ABSTRACT FROM AUTHOR] |
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