汽爆秸秆固态发酵微生物油脂及其热解制备生物柴油
文献类型：学位论文
| 作者 | 彭小伟 |
| 学位类别 | 博士 |
| 答辩日期 | 2008-04-29 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 过程工程研究所 |
| 导师 | 陈洪章 |
| 关键词 | 秸秆 固态发酵 微生物油脂 热解 生物柴油 |
| 其他题名 | Production of Single Cell Oils from Steam-exploded Straw in Solid-stated Fermentation and Pyrolysis of Fermented Mass for Producing Biodiesel |
| 学位专业 | 生物化工 |
| 中文摘要 | 随着生物柴油产业的发展，油脂来源不足问题日渐突出，寻找新的油脂来源是各国研究的热点，丰富的秸秆资源是可再生能源生产的重要原料，利用秸秆生产微生物油脂，可能为生物柴油生产开辟新的油脂来源，本论文对秸秆原料转化微生物油脂过程涉及的关键问题进行了研究，同时探索了富含微生物油脂的固态发酵物热解生成生物柴油的途径。 论文的主要研究结果和结论如下： 1、适宜于汽爆秸秆固态发酵微生物油脂菌株的筛选 已有的研究表明，植物内生真菌是由植物病原菌演化而来，其侵染植物的过程本身就是水解木质素纤维素的过程，同时，植物内生真菌能产生与其宿主相同或相似的代谢产物，油脂植物内生真菌中可能储藏着丰富的产油脂菌株。因此我们从油脂植物内生真菌中寻找具有降解纤维素能力的产油脂菌株。通过考察不同地区的7种油脂植物内生真菌产油脂特性，发现油脂植物内生真菌中有大量的产油脂菌株存在，在分离的菌株中，产油脂菌株占总菌数的48.9%，选出其中26株油脂高产菌株作进一步研究发现，它们都能分泌纤维素酶和木聚糖酶且能利用秸秆固态发酵产微生物油脂，油脂产量为19～42mg/g干底物，油脂植物内生真菌的这些特性为秸秆发酵微生物油脂开辟了新的菌种资源。 2、汽爆秸秆固态发酵微生物油脂 充分利用汽爆秸秆固态物料特性和固态发酵节能减排的优势，论文主要采用固态发酵的方式生产微生物油脂。首先，以筛选到的产油脂能力最强的小球壳孢菌（Microsphaeropsis sp.）为生产菌，进行了汽爆秸秆固态发酵生产微生物油脂研究，考察了固态发酵工艺及油脂积累规律，在优化条件下，油脂产量为80.0mg/g干底物，纤维素和半纤维素的降解率分别为76.4％和68.8％；同时考察了该菌株利用秸秆汽爆过程半纤维素降解产生的可溶性糖（主要为木聚糖）发酵微生物油脂工艺和方法，该菌株能分泌木聚糖酶降解木聚糖并利用木糖发酵微生物油脂，发酵脂肪系数为14.2％，为秸秆中半纤维素的利用提供新的途径。另外，研究了拉曼被孢霉（Mortierealla ramanniana）固态发酵汽爆秸秆产生多不饱和脂肪酸――γ-亚麻酸（GLA）和花生四稀酸(ARA)的工艺和方法以及多不饱和脂肪酸积累的规律，在优化条件下，多不饱和脂肪酸的产量为5.6mg/g干底物。研究发现该菌株多不饱和脂肪酸的生成主要发生在油脂合成的后期，而当发酵后期培养基碳源缺乏时，菌株能用自身积累的油脂维持代谢。研究了压力脉动固态发酵罐发酵对油脂和多不饱和脂肪酸积累的影响，发现压力脉动能加强菌体的呼吸作用从而能缩短发酵周期，但油脂产量和多不饱和脂肪酸的产量基本保持不变。 在固态发酵研究过程中，建立了近红外光谱（NIR）快速分析秸秆固态发酵物中油脂含量的方法，与传统的化学方法相比，该方法快速、清洁、准确，可以在短时间内分析大量样品，节省时间和有机溶剂，为今后秸秆固态发酵微生物油脂的研究奠定了方法基础。 3、富含微生物油脂的固态发酵物热解研究 针对固态发酵物中油脂提取困难，后续的油脂精制和转酯化反应过程复杂的问题，探索了富含微生物油脂的固态发酵物热解生成生物柴油的途径。考察了汽爆秸秆小球壳孢菌（Microsphaeropsis sp.）固态发酵物在管式固定床热解反应器中的热解规律，发现发酵物热解液相产物中有十六烷酸甲酯和9－十八稀酸甲酯生成，且人造沸石作催化剂热解能提高十六烷酸甲酯和9－十八稀酸甲酯的转化率，在用量为热解物料的20％（W/W）时，它们的转化率分别由6.27％提高到30.0％和由4.18％提高到10.26％，推断它们的主要生成途径为物料中纤维素和半纤维素热解产生的甲醇与油脂转酯化反应而形成。本研究首次发现含油脂物料热解生成脂肪酸甲酯，为生物柴油的生产提供了新的思路。 |
| 英文摘要 | The main barrier to the production of biodiesel is the shortage of oil or fat. Finding new oil or fat resource becomes a hot research task. Using straw as the substrate to produce single cell oil (SCO) may be a potential oil resource for the production of biodiesel because plenty of straw is produced every year and it is the main resource for producing renewable energy. This dissertation aims to produce SCO from cheap and abundant straw. The key problems in the process of converting straw to SCO were researched and a new way for producing biodiesel from the fermented mass containing SCO by pyrolysis was explored. The principal results and conclusions of this research are as follows. 1. Screening of the stains which fit for producing SCO from straw in solid-state fermentation (SSF). It was proved that endophytic fungi were evolved from plant pathogens, their ability of utilizing lignocellulose available in cell walls would be important for successful interior colonization and they can produce the same metabolites as their hosts. Therefore, we selected the endophytic fungi in oleaginous plants to screen the strains which have the ability of secreting lignocellulase for producing SCO from straw. One hundred and forty-one isolates of endophytic fungi were obtained from stems of seven oleaginous plant species. The abilities of accumulating SCO of these isolates were examined. It was found that 48.9% of the isolates can accumulate SCO. Twenty-six isolates which had higher SCO yields were selected for further research. They all can secret cellulase and xylanase and can produce SCO from straw in solid-state fermentation (SSF) with the SCO yields of 19- 42 mg/g dry substrate. These results show that endophytic fungi in oleaginous plants may be potential SCO producers by utilizing straw as the substrate. 2. Production of SCO from steam-exploded wheat straw (SEWS) in SSF. SSF was employed to produce SCO because of the solid characteristic of straw and the advantages of SSF. Microsphaeropsis sp., an endophytic fungi isolated from Sabina chinensis, was used to produce SCO in SSF from SEWS. The effects of SSF parameters on SCO yield were examined. Under the optimized conditions, the SCO yield was 80 mg/gds, and the enzymic hydrolysis rates of cellulose and hemicellulose of the substrate were 84.5% and 64.8%, respectively. Microsphaeropsis sp. can also accumulate SCO with soluble sugars produced from hemicellulose of straw during exploded, which gives a new way to utilize hemicellulose of the straw. In addition, Mortierealla ramanniana was used to produce polyunsaturated fatty acids (PUFA): γ-linolenic acid (GLA) and Arachidonic acid (ARA) from SEWS in SSF. Under the optimized conditions the PUFA yield was 5.6mg/g dry substrate. PUFA was produced mainly at the end of the state of lipid synthesis. When carbon source in the medium was absent at the end of fermentation the strain could consume the accumulated lipid. When solid-state fermentation was held in air pressure pulsation reactor the fermentation cycle was shortened but the yields of SCO and PUFA were almost unchanged. A rapid and accurate method for estimation of SCO content of fermented mass sample fermented by oleaginous fungi in solid-state fermentation was established using near infrared reflectance spectroscopy (NIRS). With this mothed much time and reagent will be saved. Therefore this method will provide much convenience for the research of SCO production in SSF with much less time and reagent consumption. 3. Pyrolysis of the solid-state fermented mass. The pyrolysis behaviors of solid-state fermented mass fermented from SEWS by Microsphaeropsis sp. in tubular furnace pyrolysis equipment were researched. n-Hexadecanoic acid hexadecanoic acid, methyl ester and 9-octadecenoic acid [Z], methyl ester were found in the hexane-extracted fraction of liquid product. The harvest rates of n-hexadecanoic acid, methyl ester and 9-octadecenoic acid [Z], methyl ester increased from 6.27％to 30.0％ and from 4.18％ to 10.26％, respectively when pyrolysis was performed with permutit as catalyzer by loading rate of 20% (W/W) of the fermented mass. This research found fatty acid methyl eaters, which were used as biodiesel, could be produced by pyrolysis from the mass containing lipid for the first time, hence providing a novel way for the production of biodiesel. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 167 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1118]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 彭小伟. 汽爆秸秆固态发酵微生物油脂及其热解制备生物柴油[D]. 过程工程研究所. 中国科学院过程工程研究所. 2008. |
入库方式： OAI收割
来源：过程工程研究所
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