碳源对微藻脱除烟道气NOx的影响与调控

This proposal will research denitrification of flue gas, due to nitrogen oxides (NOx) cause the atmospheric problems of haze, photochemical smog and acid rain, and the environmental NOx are mainly derived from fossil fuel combustion flue gas.This project will focus on the key technologies of biological removal of NOx from flue gas using microalgae，which carry out the mechanism of carbon source affecting the denitrification efficiency by microalgae and study the regulation strategy.First, the effects of carbon species, carbon supply model and other culture conditions on the efficiency of biological elimination of nitric oxide from flue gas are going to be studied, as well as microalgae growth and valuable byproducts accumulation efficiency are going to be examined. The feasibility of that CO2, organic carbon source in waste water and agricultural waste straw hydrolysate act as the carbon source of microalgae to remove NOx, is to be detected. Second, analysis the mechanism of how carbon source influence the bio-denitrification efficiency. According to the mechanism, to improve the efficiency of denitrification by microalgae as the main goal, to get valuable byproducts as a secondary objective, bio-denitrification regulation strategy based carbon supply is going to be established to achieve high NO removal rate and get valuable byproducts such as bio-oil, protein, starch. This proposal will contribute to develop non-polluting, economical and reasonable new air pollution control technologies.

针对氮氧化物（NOx）是形成灰霾、光化学烟雾和酸雨等大气环境问题的主要元凶和NOx主要来源于化石燃料燃烧产生的烟气的问题，开展烟道气脱硝技术的研究。本项目研究利用微藻脱除烟道气中NOx的关键技术，拟从调整碳源角度开展微藻脱硝效率的影响机理和调控研究。项目首先研究碳源种类、供给模式以及其他辅助培养条件对微藻去除烟道气中NOx的影响，兼顾研究上述条件对微藻生长及微藻积累有价值副产品的影响，并考查CO2、污水中碳源有机物、秸秆水解物等环境废弃碳源作为微藻脱硝碳源的可行性。其次分析碳源影响微藻脱硝效率的机制，并依据此机制，以提高微藻脱硝效率为主要目标，以获得有价值副产品为辅助目标，建立基于碳源供给的微藻脱硝调控策略，最终达到提高微藻脱硝效率并获得饲料、生物油脂、蛋白质、淀粉等有价值微藻副产品的目的。本项目的研究成果将为开发无污染、经济合理的新型大气污染治理技术做出贡献。

本项目筛选获得了2株脱硝固碳藻种：微茫藻Micractinium sp.PFA和小球藻Chlorella sorokiniana PF1，开展了两株微藻的生长性能、对烟道气环境、生活污水环境和对典型有机无机碳源的适应性研究。微茫藻Micractinium sp.PFA能够适应烟道气和生活污水环境，易于利用CO2，不易利用葡萄糖碳源但是能够利用污水中小分子有机碳源，因此设计生活污水-烟道气混合碳源培养模式的系统，利用微茫藻Micractinium sp.PFA直接脱除烟道气中NO分子和吸收CO2。通过添加助溶剂、优化反应器结构等优化Micractinium sp.PFA的脱硝固碳条件。在通实际燃煤电厂烟道气的条件下，系统脱硝效率可达60%，NOx排放浓度15ppm，符合超低排放标准；同时生活污水出水的TN和TP均符合国家污水排放一级A标准；其CO2表观去除率达到5%，固碳效率可达248 mg L-1d-1；获得微藻生物质的含糖量高达60%，大部分是硫酸粘多糖，具有功能糖开发潜力。.小球藻Chlorella sorokiniana PF1具有高效利用有机碳源和水中NO3-N的能力。本项目研究了该藻对37种常用有机碳源的利用情况，考查了玉米秸秆水热处理液作为Chlorella sorokiniana PF1培养的碳源的可行性。结果表明，乙酸可以促进生长，在缺氮条件下能促进细胞中多糖的合成，但充足条件下促进蛋白质的合成。推测Chlorella sorokiniana PF1细胞内存在乙酸快速合成乙酰-CoA的途径，积累的乙酰-CoA会抑制糖酵解作用，从而促进多糖的存储；在氮充足时，进入TCA循环的乙酰-CoA增多以保证其中间产物ꭤ-酮戊二酸与氨基合成氨基酸，从而多糖比例下降，蛋白质含量增加。Chlorella sorokiniana PF1可以耐受预处理液中的糠醛和羟甲基糠醛，能快速利用液体中的葡萄糖、木糖和乙酸等有机质，具有吸收NOx氧化后水溶物的潜力，N的脱除效率可达175mg L-1d-1。在氮缺乏时利用玉米秸秆预处理液培养的Chlorella sorokiniana PF1生物质含糖量高达40%，在氮源充足时，其蛋白含量高达39.4%，具有单细胞蛋白饲料开发潜力。.