The fermentation process development of Rhodotorula glutinis by using seawater and crude glycerol

• Main Authors: Liang, Wei-Siang, 梁惟翔
• Other Authors: Yen, Hong-Wei
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/fn7qkr

碩士 === 東海大學 === 化學工程與材料工程學系 === 105 === Rhodotorula glutinis (BCRC 22360) is an oleaginous yeast that can accumulate high content of total lipid, which is suitable as a microbial oil producer for the production of oil feedstock converted to biodiesel. With oil price increasing, a large of crude glycerol accumulates as biodiesel productivity rising. Although the prices of waste crude glycerol was too low, waste crude glycerol refined to purify it by complicate and costly process. To find out a new usage of crude glycerol has become an important issue for global research. In Taiwan, 1.66 billion tons of freshwater are consumed annually in industry that faced with greater the risk of water shortages. However, Taiwan is an island state which have rich marine resources. Maybe the problem of limited freshwater resources can be solved by using seawater to cultivate R. glutinis. In this study, the effects of fermentation strategy on cell growth and lipid production in bioreactor by using crude glycerol as carbon source and seawater were investigated. The effects of medium ingredients and environmental cultivation conditions on the growth of cell and the content of lipid in the shaker flask experiments. First, it was found that, the experiments by using seawater can lead to biomass of 5.73 g/L and lipid content 29.17 %. Preliminary result shows R. glutinis can grow in the environment of seawater；The experiments by two stage control cause the reduction on biomass concentration but can improved by 1.61 times in lipid content, infer that in order to adapt low temperature cause lipid rapid accumulation. The experiments by adding palm oil and waste cooking oil are found to 3% of the appropriate addition；By reduce sterilization temperature in order to lower the cost. Non-sterile can’t avoid contamination. But at 80℃sterilization, we can get the biomass of 7.06 g/L and total lipid of 2.23 g/L. From the results, 80℃sterilization can effective avoid contamination same as normal sterilization process (121℃). Three parts were discussed in the trial of scale up experiment, including (1) In a 5L airlift bioreactor, the effects of environmental cultivation conditions on the total lipid production were evaluated by changing proportion of seawater. It was found that the addition of fifty percent seawater can lead to biomass of 18.4 g/L and the max total lipid of 6.84 g/L which is almost the same as the freshwater medium. (2) Production cost and growth of cell adding waste cooking oil is better than palm oil. The experiment of adding 3 % waste cooking oil was discussed that scaled up by using the 5 L stirred tank reactor and 5 L airlift. It was found that adding waste cooking oil can promote the growth of cell significantly, which could obtain 25.8 g/L of biomass and 50.61 % of lipid content by using 5 L stirred tank reactor. While getting 22.3 g/L of biomass and 37.54 % of lipid content by using 5 L airlift. Comparing the two reactors, 5 L stirred tank reactor was better than another one. Keywords: Rhodotorula glutinis、seawater、crude glycerol、waste cooking oil