【作者】 纪雁；

【导师】 裴海燕；

【作者基本信息】 山东大学 ， 环境工程， 2014， 博士

【摘要】 由于微藻具有生长迅速、油脂含量高、占地面积小等优点,作为第三代生物能源正在受到广泛的关注和研究。微藻除了可以用来生产生物燃料(如生物柴油、生物乙醇等),还可以用来生产动物饲料、食品添加剂、高附加值产品等(如保健品、化妆品)。微藻生长速度快倍增时间短,它的生长速率几乎是高等植物的100倍。但是由于培养系统内部的光衰减以及CO2供应限制,微藻的光能自养生长速率要远远低于异样培养或是兼养培养的生长速率。在一般的光能自养培养条件下,微藻的生物质浓度通常都会低于1g/L。当微藻被同时供给C02和有机碳源的时候,微藻进行兼养生长。在兼养生长模式下,微藻对光线的依赖程度大大减弱,同时其生长速率得以大大提高。但是向无机培养基中直接添加有机碳源将会增加微藻培养的成本,进而制约微藻的商业化生产。为了降低生产成本,人们开始探索使用有机废水作为培养基直接培养微藻。使用该方法可以将废水中的有机物通过藻细胞转化成有用的生物质,既实现了微藻的低成本培养,又有效地处理了污水。在东亚和东南亚地区,味精作为一种增鲜剂被广泛地应用在食品生产当中。中国是味精生产大国,中国的味精年产量几乎占到世界总产量的一半。而味精生产会产生大量的有机废水,这种棕黑色的废水具有高COD、高NH3-N、高硫酸盐、低pH等特点。若无切实有效的处理,大量的味精废水将会引发严重的环境污染。本论文从微藻生长速率、微藻生物质组成等方面评价了使用味精废水做为培养基培养小球藻的可行性,考察了营养物质浓度、光照强度等对小球藻的影响；最后从节约水资源、降低生产成本的考虑出发,本文对养藻剩余培养液进行生物强化处理,以对其进行循环利用。论文的研究内容主要包含以下几部分：1.对使用味精废水培养小球藻的可行性进行评价,研究不同味精废水浓度对小球藻生物质产率和生化组分的影响。实验中将经过稀释、灭菌处理的味精废水直接用来培养小球藻,结果发现小球藻生长良好,与无机培养液培养的对照组相比,小球藻的生长得到极大的促进。当使用稀释100倍的味精废水时,最后得到的小球藻生物质浓度(1.02g/L)和生物质产率(61.47mg/L·d)最大。经过对小球藻的各项生化组分进行检测分析发现,使用味精废水培养出的小球藻蛋白含量最高(36.0-50.6%),总脂和总糖含量相对较低,分别为13.5-25.4%、8.9-20.1%。另外,小球藻蛋白质营养质量和不饱和脂肪酸含量都得到显著提高。因此,味精废水是培养小球藻的一种非常理想的培养基。2.光照是微藻培养中最重要的影响因子之一,不仅可以影响微藻的生长速率还可以影响微藻的生化组成。本文在实验室条件下研究了光照强度对特定培养液-味精废水中小球藻生长及生化组分的影响。直接使用稀释100倍的味精废水为培养液,设置6个不同的连续光照梯度,分别为：0μmol/m·s,30μmol/m·s,90μmol/m·s,150μmol/m·s,200μmol/m·s和300μmol/m·s。培养实验在25℃光照培养箱中进行。实验结果表明,当低于光饱和点时光照强度的增加可以极大地促进小球藻在味精废水中的生长。在150μmol/m·s光照强度下,培养7天后小球藻生物质浓度最高(1.46g/L),在培养前7天的平均比生长速率达0.79/d。在由低到高4个不同光密度下,小球藻的油脂含量分别为12.6%、17.7%、16.9%、30.5%、21.4%和23.6%。光照强度对小球藻的蛋白质和总糖含量影响正好相反。3.将微藻收获以后,剩余的培养液仍含有较高的营养物质,色度、浊度也都比较高,若是直接用作源水稀释味精废水可能会导致稀释后废水的色度、浊度更高,阻碍光线传递,进而影响微藻的生长。因此,本文对养藻废水进行生物强化处理,以期降低其中的有机物含量,同时降低废水的色度和浊度。经过处理的养藻废水,将被作为养藻水源重复使用。本文使用生化绵和希拉环两种填料构建海绵固定化系统,经过接种活性污泥、5天闷曝挂膜,海绵固定化微生物系统基本构建完成,该系统对污水COD去除率达90%左右,对TN、氨氮的去除率也均在50%以上。实际运行过程中,通过投加反硝化细菌LZ-4、XP-2,加快了固定化微生物系统对废水处理过程中亚硝氮的转化,降低了亚硝氮的积累浓度,进而提高了对TN的去除效果。进过46h的处理,废水色度、浊度分别降为10PCU、5NTU。更多还原

【Abstract】 Microalgae investigation has been focused on in research all over the world. It could be used to produce animal feed, food additives, high-value added products (such as health supplements, cosmetics et al.), especially biofuels (such as biodiesel, bioethanol), due to its certain excellent advantages such as rapid growth, the least land demand, high biochemical compositions (protein, lipid). Microalgae could double their biomass within one day and their growth rate is100times that of terrestrial plants. Nonetheless, compared with heterotrophic or mixotrophic cultivation, the microalgae usually grow slowly in photoautotrophic culture due to the light attenuation. The algal biomass is usually not more than1g/L in photoautotrophic cultivation. Mixotrophic growth occurred when the microalgae are provided with CO2and organic carbon sources simultaneously. That could greatly reduce the dependence on light needed for pure photoautotrophic growth, stimulate the algal growth and increase the cells density significantly. However, the high cost of adding organic carbon to the medium will make mixotrophic cultivation uneconomical, In order to reduce the product cost, many researchers have explored techniques to culture microalgae with organic wastewater. By this means, nutrients from wastewaters are transferred to algal biomass, achieving economical microalgae cultivation and efficient wastewater treatment simultaneously. Because of the good performance of Chlorella vulgaris in mixotrophic cultivation, it was chosen as the model organism in this study.Monosodium glutamate (MSG) as a flavor enhancer is extensively used in food products throughout east and south-east Asia. The MSG production in China accounts for about half of world’s total output. After extraction of MSG from fermentation liquor the residual dark brown wastewater and effluent have high concentrations of COD, NH3-N, sulfate and a strong acidity. Without reasonable treatment the monosodium glutamate wastewater (MSGW) would cause serious pollution to the environment and damage to the ecology. As MSGW contains abundant nutrient substance, it could be feasible to reuse these organic substances using ecotechnological methods. The main works of this study were as follows:This paper seeks to evaluate the feasibility of growing Chlorella vulgaris with MSGW and assess the influence of MSGW concentration on the biomass productivity and biochemical compositions. The MSGW diluted in different concentrations was prepared for microalga cultivation. C. vulgar is growth was greatly promoted with MSGW compared with the inorganic BG11medium. C. vulgaris obtained the maximum biomass concentration (1.02g/L) and biomass productivity (61.47mg/L-d) with100-time diluted MSGW. The harvested biomass was rich in protein (36.01-50.64%) and low in lipid (13.47-25.4%) and carbohydrate (8.94-20.1%). The protein nutritional quality and unsaturated fatty acids content of algal increased significantly with diluted MSGW. These results indicated that the MSGW is a feasible alternative for mass cultivation of C. vulgaris.Light is one of the most important factors affecting microalgae growth and biochemical composition. The influence of illumination intensity on the biomass productivity and main composition of Chlorella vulgaris cultivated in diluted MSGW was investigated in laboratory. The Chlorella vulgaris was cultivated aseptically in100-fold diluted MSGW at four continuous illumination intensities (0,30,90,150,200and300μ mol/m2-s) at25℃. The growth of Chlorella vulgaris was stimulated greatly by the increasing of illumination intensity. Under150μ molm-2s-1, the microalgae obtained the maximum biomass concentration (1.458g/L) at the7th day and the greatest average specific growth rate (0.79d-1) of the first7days culture. The lipid contents under0,30,90and150μ molm-2s-1were12.6%,17.7%,16.9%,30.5%,21.4%and23.6%, respectively. The effects of illumination intensities on the contents of protein and carbohydrate were adverse.After microalgae harvest, the residule medium still contained abundant of nutrients, and high. If it is directly used to dilute the monosodium glutamate wastewater without treatment, that would lead to higher chromaticity and turbidity of the medium, blocking the light transmission. As a resoult the growth of microalgae will be negatively affected. In order to reduce the content of organic matter and decrease the chromaticity and turbidity of wastewater at the same time, the residule medium was excited to be treated by biological technology. We used two kinds of filters to conduct a immobilized biosystem. After inoculation with activated sludge and biofilm formation in the following 5days, the treatment efficiency of the immobilized biosystem on sewage was very well. The removal rate of COD, TN reached90%,50%respectively. During the actual operation process, we added two kinds of denitrifiers to the immobilized biosystem to enhance the contaminant removal. After46h the nitrogen removal was enhanced, the accumulation of nitrate during treatment was reduced. The chromaticity and turbidity of the effluent were10PCU,5NTU, respectively. It could be reused as water resource to dilutted the MSGW for microalgae cultivation.更多还原