【作者】 张华；

【导师】 沈英；

【作者基本信息】 福州大学 ， 车辆工程， 2014， 硕士

【摘要】 能源微藻在生物燃料生产方面的优势引发巨大关注。然而,目前微藻生物柴油技术研究也面临着培养成本过高和微藻培养生物量密度低,采收困难的发展应用瓶颈。微藻吸附式固定化培养技术具有生物质收获方便,产量高等优点,也有与普通悬浮培养的不同之处。论文通过在新型生物反应器上微藻生物膜的培养,从胞外产物(Extracellular polymeric substances,EPS)特性和环境因素方面研究生物膜的生长、微藻生物质的高效获取以及提高微藻油脂产量的新途径,以期为生产实践提供科学依据和理论支持。具体内容与结论有：(1)研究光稀释式反应器上进行微藻生物膜培养的基本方法,比较不同培养条件、藻种因素和反应器环境下的生物膜的培养。光稀释式反应器能源利用率和生物膜产量高于层级式平板反应器。Chlorococcum sp,在畜禽养殖污水的生物膜产量高于Basal，最高产率7.23g/m2/day。培养基理化性能方面,氮和磷是影响微藻吸附和生物膜生长的最重要的营养元素。氮抑制处理的Chlorococcum sp吸附率增高7.6%,生物膜产率降低。(2)研究微藻生物膜胞外聚合物EPS对生物膜的影响,解释EPS在生物膜形成和生长过程中的作用机理。EPS有助于微藻初始和继发性吸附,促进生物膜形成。EPS含量随培养天数增加而增高,生物膜随EPS含量的增加而增大。EPS含量受环境和培养因素的影响。B. braunii生物膜的EPS含量高于Chlorococcum sp.,污水培养含量大于Basal培养。多糖和蛋白质是EPS最主要成分,且以多糖成分居多。EPS中T-EPS最高,S-EPS次之,L-EPS最少,T-EPS部分有助于生物膜吸附。后期多糖比例降低,蛋白质升高,生物膜出现部分脱落。(3)研究各种培养基理化参数和环境条件因素对生物膜的影响,以改善微藻生物膜吸附效果,提高生物膜产量。运用Plackett-Burman设计原理筛选得到三个显著因素：光照强度、接种浓度和FeSO4·7H2O浓度。中心组合实验(CCD)拟合的模型能够很好地预测响应值,优化结果分别为11234.571ux、 0.25g/L和81.88mg/L,最高生物膜产率5.33g/m2/day。(4)探索微藻吸收利用EPS组分的可行性,考查EPS刺激条件下B. braunii生物膜油含量变化、甘油三酯的组学变化及机理。B. braunii生物膜在污水中产量高于Basal,但油含量略低。抑制和EPS刺激培养后油含量分别提高至42.2%、51.3%,合油脂产率844mg/m2/d. 1000mg/m2/d<。B. braunii可以吸收EPS中糖和蛋白成分积累油脂,使得中性脂肪TAG比例得以增高(TAG约占总脂的94%)。脂肪酸组成得到改善,饱和脂肪酸比例(C16：0,C18：0等)增大,不饱和脂肪酸(C18：1,C18：2等)降低,油脂品质符合内燃机燃料的特征。转化利用生物膜胞外产物EPS合成油脂,为获得高产量和高品质的生物柴油原料提供新途径。更多还原

【Abstract】 The advantages of energy microalgae cause great concern in biofuel production. However, the current research of microalgae biodiesel also faces the development and application bottleneck:one is the huge cost in microalgae culture, the other is biomass recovery difficulties. Immobilization technology of microalgae attaching culture is conveniently carried, high output. This topic through cultivating microalgae biofilms in a novel bioreactor, Investigated biofilms growth, biomass efficiently harvested and new lipids yield promoting approach by understanding the characteristics of extracellular polymeric substances (EPS) and the Influences of environmental factors, demonstrated the feasibility and innovation of microalgae attaching culture. The specific contents and conclusion are as follows:(1) Investigated the basic culture skills on optical dilution bioreactor for microalgae biofilm, compared growing states in different culture conditions (the physicochemical properties of medium), species (nitrogen inhibited or not) and bioreactor types. Energy efficiency and biofilm productivity in light-dilution-type reactor were higher than the level-flat-plate reactor. Chlorococcum sp. obtained higher biofilm mass (7.23g/m2/day) in livestock wastewater than Basal medium. Nitrogen inhibited algal strain with higher attached rate (78.95%) than non-inhibited (73.35%). Nitrogen, phosphorus are the most important nutrient elements influencing absorption rate and the biofilm growth.(2) Researched the effects of extracellular polymeric substances (EPS) on microalgae biofilm, recognized action mechanism of EPS on biofilm formation and growth process. EPS effected initial adsorption of microalgae, promoted the formation of biofilm, the content of EPS increased along with the days, biofilm production Increased with increasing EPS content. The EPS content were significantly affected by environmental conditions and culture parameters. The EPS of B. braunii was more than Chlorococcum sp., EPS content in sewage medium was more than Basal. Polysaccharide and protein were the main components of EPS, Polysaccharide components was higher than protein. In three parts of EPS, T-EPS is the highest, followed by S-EPS, L-EPS the least, T-EPS benefited microalgae attachment. In the final stage proportion of polysaccharide decreased, protein increased, and biofilm detachment arose.(3) Researched effects of various culture physicochemical parameters and environmental conditions on microalgae biofilm, improved attached rate, increased the yield. Using Plackett-Burman to screen the most remarkable three factors:light intensity, inoculation (Chlorococcum sp.) concentration and FeSO4·7H2O concentration. Further, Central composite design (CCD) optimization was carried out and the model could predicted the response value well. CCD optimization results were 11234.57lux,0.25g/L and 81.88mg/L, the best biomass productivity was 5.33 g/m2/day.(4) Explored the feasibility of absorbing and utilizing B. braunii biofilm EPS and the mechanism of lipids content and triglyceride group change in EPS stimulated culture. B. braunii biofilm yield in the sewage was higher than that of Basal medium, but lipids content was slightly lower. After 10 days nitrogen inhibited stimulation and EPS stimulation culture, lipids content increased to 42.2%,51.3%, the oil yields were 844mg/m2/d,1000 mg/m2/d in a total of 30 days two-stage culture. B.braunii could absorbed polysaccharide and protein components in EPS for lipids accumulation and increased the ratio of neutral triacylglycerols (TAG), fatty acid composition quality improved. Among the composition of TAG, saturated fatty acid (C16:0, C18:0, et al) increased, unsaturated fatty acid (C18:1, C18:2, et al) decreased, In accordance with the features of internal combustion engine fuel quality. It is probably a novel approach to obtain high productivity and quality biodiesel stock that utilize biofilm EPS for lipids accumulation.更多还原