生物浸矿过程微生物的高密度培育

The Progress of the former project of Youth National Natural Science Fundation of China: firstly, 216 key genes involed in leaching function were identified from the whole 3217 genes in genome after genome-wide bioinformatic data mining and gene transcription, expression of Acidithiobacillus ferrooxidans under different culture conditions. Then, some proteins of the key genes were characterized and identification of function. Finally, a map for biological leaching effect network in details was built, which revealed the bioleaching mechanism. The main academic achievement: during the study period, 19 papers of the researchers in the project group were published and many articles are on peer review.. The content of the application project: the key problems in research on bioleaching at present are that leaching rate was slow, leaching rate was low. From it can be known from the previous research that the growth of microbes and the mineral leaching rate are closely related, the quantity of microbes in leaching system is directly related to the mineral leaching effect. So, the project plans to carry out the study of high-cell density cultivation of microorganisms in bioleaching process, including the following contents: to investigate the limit factors in high-cell density cultivation of microorganism of bioleaching process; to attain the breakthrough methods for the limit factors; taking mineral leaching efficiency as the goal, through optimizing the control condition, to improve microbial culture with high-cell density to strengthen bioleaching; to form the high-cell density cultivation of microbial leaching technology with cost saving and convenient industrial application.

前一青年科学基金项目进展：通过对嗜酸氧化亚铁硫杆菌全基因组生物信息学挖掘和不同培养条件下基因转录、表达差异研究，从全基因组3217个基因中识别出浸矿功能关键基因216个，对其中若干进行了表征和功能鉴定，最终构建了生物浸矿作用网络细节图，揭示了微生物浸矿的机理。取得的主要学术成绩：项目组研究人员研究期间共发表论文19篇，另有多篇文章正在审稿中。. 申请项目的研究内容：生物浸矿目前存在的关键问题是浸出速率慢、浸出率低。由前一项目研究得知，微生物的生长和矿物浸出紧密相关，浸矿体系微生物的数量直接关系到矿物的浸出效果。为此，本项目拟对生物浸矿过程微生物的高密度培育进行研究，具体内容包括：探明浸矿过程微生物高密度培育限制因素的情况；寻找限制突破方法；以矿物浸出效率为目标，优化操控条件，实现微生物高密度培育，强化生物浸矿；形成成本节约，工业应用方便的微生物高密度培育浸矿新技术。

环境友好工艺简廉的生物冶金技术存在浸出速率慢、浸出率低的关键难题。项目提出强化浸矿过程生物作用因素以提高生物浸出效率的策略，从工艺、物化条件、微观机理、群落结构、转录组蛋白组、功能基因蛋白、软件开发辅助等不同方法层次角度，研究了浸矿过程微生物的高密度培育。结果表明，在浸矿微生物密度提升过程各阶段，不同的限制瓶颈相继出现。生物浸矿是化能自养体系，直接固定空气中的氮气为氮源为高耗能步骤使微生物的密度难于跨越10的7次方个每毫升台阶，直接利用空气中的二氧化碳为碳源因含量低传质不足使微生物的密度难于跨越10的9次方个每毫升台阶。浸矿过程微生物的高密度培育需要综合运用多种办法优化条件来实现，包括加入能直接提供铵根离子的氮源避开耗能环节，利用或加入浸矿液中能缓释二氧化碳的物质随时直接供应碳源，分批补料加入适合比例的速效能源物质，优化微生物生长最佳温度、pH、电位等条件，采用搅拌或通透性高的筑堆技术，鼓风供氧，及时导出浸出液中的微生物代谢产生的有害物质和金属离子，优化浸矿微生物菌群结构，优化工艺等综合措施，可使微生物的密度跨上10的10次方个每毫升台阶。项目的研究为生物浸矿效率提高开辟了有效途径。