Optimization of Protein Overproduction by Recombinant Microorganisms

这份补充申请将支持三名本科生。他们的简历也包含在这份请求中。拟开展的工作涉及三个本科科研项目，具体如下：质粒丢失的实验研究本科生将使用含有编码质粒以过量产生蛋白质的细菌进行连续发酵。将采集样品并进行分析，以便将质粒损失与细胞生长和蛋白质生产速率联系起来。结果将与数学模型进行比较。2. 该本科生将进行摇瓶实验和10-15升发酵罐的放大实验，以测试和进一步开发酵母分泌过量转化酶的数学模型。3. 通过絮凝和沉淀的选择性回收本科生将运行一个连续的循环生物反应器，该反应器配置为在来自快速增长的非絮凝菌株的竞争中保持较慢增长的絮凝菌株。他或她还将进行混合培养的共絮凝研究，并测量两种菌株的分离程度，这可以通过在倾斜沉淀器中沉淀来实现。这三名本科生都将接受美国国家科学基金资助的共同项目负责人之一的指导，并至少每两周与他们见面一次。此外，由国家科学基金资助的研究生将被指派为每位本科生的导师，以协助本科生开展每个项目的日常方面。

Three undergraduate students are to be supported by this supplementary request. Their resumes are included with this request. The proposed work involves three undergraduate research projects which are as follows: 1. Experimental Study of Plasmid Loss The undergraduate student will run continuous fermentations with bacteria containing plasmids encoded to overproduce a protein. Samples will be taken and analyzed in order to correlate plasmid loss with cell growth and protein production rate. Results will be compared with a mathematical model. 2. Modeling and Control of Invertase Overproduction The undergraduate student will perform shake flask experiments and scale-up experiments with a 10-15 liter fermentor in order to test and further develop a mathematical model of the secretion of overproduced invertase by yeast. 3. Selective Recycle via Flocculation and Sedimentation The undergraduate student will run a continuous recycle bioreactor configured to maintain a slower growing flocculent strain in spite of competition from a faster-growing non- flocculent strain. He or she will also perform coflocculation studies with mixed cultures and measure the degree of separation of the two strains that can be achieved by sedimentation in a inclined settler. Each of the three undergraduate students will be supervised by and meet at least biweekly with one of the co-PIs on the NSF grant. In addition, a graduate student supported by the NSF grant will be assigned as a mentor to each undergraduate student in order to assist the undergraduate with the day-to-day aspects of carrying out each project.