While the expansion of the erythritol production industry has resulted in unprecedented production of yeast cells, it also suffers from a lack of effective utilization. β-Carotene is a value-added compound that can be synthesized by engineered Yarrowia lipolytica. Here, we first evaluated the production performance of erythritol-producing yeast strains under two different morphologies and then successfully constructed a chassis with yeast-like morphology by deleting Mhy1 and Cla4 genes. Subsequently, β-carotene synthesis pathway genes, CarRA and CarB from Blakeslea trispora, were introduced to construct the βcarotene and erythritol coproducing Y. lipolytica strain ylmcc. The rate-limiting genes GGS1 and tHMG1 were overexpressed to increase the β-carotene yield by 45.32-fold compared with the strain ylmcc. However, increased β-carotene accumulation led to prolonged fermentation time; therefore, transporter engineering through overexpression of YTH1 and YTH3 genes was used to alleviate fermentation delays. Using batch fermentation in a 3 L bioreactor, this engineered Y. lipolytica strain produced erythritol with production, yield, and productivity values of 171 g/L, 0.56 g/g glucose, and 2.38 g/(L•h), respectively, with a concomitant βcarotene yield of 47.36 ± 0.06 mg/g DCW. The approach presented here improves the value of erythritol-producing cells and offers a low-cost technique to obtain hydrophobic terpenoids.
This paper summarily introduced the production safety problems during operation process of fishing ships in China. In order to solve these problems, we present the range and significance of utilizing AIS technology in the fishing ships management, and summarily introduced the scale of AIS technology construction in coastal region of China. What's more, this paper expounds construction scheme of AIS system, detailedly designs AIS terminal architecture, technical parameters, and the solution of AIS data transmission between fishing boats. We summarized the function of this system and specific problems during the managements of fishing ships, and present matters that need attention during the utilization of AIS technology. By building AIS system, we could reduce collision accidents, improve rate of successful rescue toward ships in distress, protect fisherman's lives and property security, all above have positive effects in promoting the construction of "safe fishing".
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