通过构建絮凝突变菌株，研究基因敲除前后地衣芽孢杆菌细胞表面物质组成及微生物胶体稳定性的变化，解析絮凝基因对细胞表面特性的影响机制，获得影响细胞胶体稳定性的关键基因。进而研究关键基因对细胞絮凝的影响规律，确立絮凝基因、微生物胶体稳定性、细胞絮凝行为之间的内在联系，阐明细菌细胞絮凝机制。利用基因工程手段对关键基因进行改造，最终实现对地衣芽孢杆菌絮凝行为的调控。在酵母细胞絮凝机制明晰之后，本项目为揭示细菌细胞的絮凝机制提供依据，对地衣芽孢杆菌全基因组学与细胞代谢机制研究具有补充意义。

Studies on the cell surface and colloid stability of B. licheniformis will be carried out with mutations of different flocculating activities by gene knockout. The effection of flocculating gene on bacterial cell surface and the interrelations between flocculating genes and microbial colloid stability and cell flocculation will be illustrated. Then site directed mutagenesis is used for mutation of the key gene regarding cell colloid stability. The molecular regulation of bacteria flocculation is finally realized. In contrast to the systematically studied flocculating yeast, this project will clarify the mechanism of bacteria flocculation, and also help to complete the genomics and the metabolism of Bacillus licheniformis.