产油毛霉菌的筛选及其油脂发酵工艺优化
发布时间：2018-08-02 15:26
【摘要】：生物柴油具有可生物降解、低毒、低排放特性,是最有前景的化石能源替代燃料,但原料油供应不足成为限制生物柴油发展的瓶颈。微生物油脂是生物柴油的潜在理想原料油,本论文拟从自然界中筛选油脂高产真菌,并对其油脂发酵工艺进行优化,取得的主要研究结果如下:(1)从牧场土壤筛选获得一株油脂含量为30.2%的真菌,其脂肪酸组份主要为油酸(46.26%)、棕榈酸(22.58%)、γ-亚麻酸(13.68%)和亚油酸(6.68%),与植物油脂肪酸组成相似,碱法制备生物柴油得率89.6%,且其生物柴油特性指标基本符合国际生物柴油生产标准,表明该菌株可作为原料油生产生物柴油。(2)根据形态学、生理生化特征及18S rDNA序列分析,对筛得的菌株进行分类鉴定。结果表明,该菌株的形态和生理特征与毛霉属真菌相似,且其18S rDNA序列与Mucor sp.EA 2010b stain ERRL的18S rDNA序列相似度为99%,因此,将其归属于毛霉,并命名为Mucor sp.RBB 1-5。(3)采用单因子实验和响应面分析优化了Mucor sp.RBB 1-5的油脂发酵工艺,发现蛋白胨较酵母粉更有利于油脂积累,其最佳培养基配方为:葡萄糖103.32 g/L,蛋白胨3.21 g/L,豆粕粉蛋白浓度3.29 g/L,KNO3 3.0 g/L,Na2HPO4 2.0 g/L,MgSO4·7H2O1.0 g/L;最佳培养条件为:初始pH 6.0,装液量50 m L/250 mL,温度28℃,培养时间5 d。在优化发酵条件下,油脂产量达10.38 g/L,相比未优化之前提高2.15倍。(4)研究了蛋白胨和酵母粉对油脂发酵的影响机制。通过分析氮源对三羧酸循环(TCA)途径中苹果酸酶(ME)活性和戊糖磷酸(PP)途径中葡萄糖-6磷酸脱氢酶(G6PDH)活性的影响,探讨氮源对油脂发酵的影响机制。苹果酸酶(ME)酶活与油脂变化趋势一致,葡萄糖-6-磷酸脱氢酶(G6PDH)活性与油脂变化无明显相关性,蛋白胨为氮源时ME酶活性高于酵母粉组,表明蛋白胨主要通过影响TCA途径,增强ME活性,进而增加还原力NADPH的供应来提高油脂产量。
[Abstract]:Biodiesel has the characteristics of biodegradability, low toxicity and low emission, so it is the most promising alternative fuel for fossil energy. However, the shortage of raw oil has become the bottleneck to restrict the development of biodiesel. Microbial oil is a potential ideal raw oil for biodiesel. In this paper, high yield fungi were selected from nature, and the fermentation process was optimized. The main results were as follows: (1) A fungus with 30.2% oil content was obtained from pasture soil. Its fatty acid components were oleic acid (46.26%), palmitic acid (22.58%), 纬 -linolenic acid (13.68%) and linoleic acid (6.68%), which were similar to the fatty acid composition of vegetable oil. The yield of biodiesel prepared by alkali method was 89.6 and the characteristic index of biodiesel was basically in line with the international biodiesel production standard, which indicated that the strain could be used as raw oil to produce biodiesel. (2) according to morphology, physiological and biochemical characteristics and 18s rDNA sequence analysis, the strain could be used as raw oil to produce biodiesel. The screened strains were classified and identified. The results showed that the morphological and physiological characteristics of the strain were similar to those of Mucor, and its 18s rDNA sequence was similar to the 18s rDNA sequence of Mucor sp.EA 2010b stain ERRL. It was named Mucor sp.RBB 1-5. (3) single factor experiment and response surface analysis were used to optimize the fat fermentation process of Mucor sp.RBB 1-5. It was found that peptone was more favorable than yeast powder for oil accumulation. The optimum culture medium was: glucose 103.32 g / L, peptone 3.21 g / L, soybean meal protein concentration 3.29 g / L, Kno 3 3.0 g / L, Na2HPO 4 2.0 g / L, MgSO 4 7H2O1.0 g / L. the optimum culture conditions were as follows: initial pH 6.0, liquid volume 50 mL / 250 mL, temperature 28 鈩，
本文编号：2159868
[Abstract]:Biodiesel has the characteristics of biodegradability, low toxicity and low emission, so it is the most promising alternative fuel for fossil energy. However, the shortage of raw oil has become the bottleneck to restrict the development of biodiesel. Microbial oil is a potential ideal raw oil for biodiesel. In this paper, high yield fungi were selected from nature, and the fermentation process was optimized. The main results were as follows: (1) A fungus with 30.2% oil content was obtained from pasture soil. Its fatty acid components were oleic acid (46.26%), palmitic acid (22.58%), 纬 -linolenic acid (13.68%) and linoleic acid (6.68%), which were similar to the fatty acid composition of vegetable oil. The yield of biodiesel prepared by alkali method was 89.6 and the characteristic index of biodiesel was basically in line with the international biodiesel production standard, which indicated that the strain could be used as raw oil to produce biodiesel. (2) according to morphology, physiological and biochemical characteristics and 18s rDNA sequence analysis, the strain could be used as raw oil to produce biodiesel. The screened strains were classified and identified. The results showed that the morphological and physiological characteristics of the strain were similar to those of Mucor, and its 18s rDNA sequence was similar to the 18s rDNA sequence of Mucor sp.EA 2010b stain ERRL. It was named Mucor sp.RBB 1-5. (3) single factor experiment and response surface analysis were used to optimize the fat fermentation process of Mucor sp.RBB 1-5. It was found that peptone was more favorable than yeast powder for oil accumulation. The optimum culture medium was: glucose 103.32 g / L, peptone 3.21 g / L, soybean meal protein concentration 3.29 g / L, Kno 3 3.0 g / L, Na2HPO 4 2.0 g / L, MgSO 4 7H2O1.0 g / L. the optimum culture conditions were as follows: initial pH 6.0, liquid volume 50 mL / 250 mL, temperature 28 鈩，
本文编号：2159868
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