米曲霉Aspergillus oryzae发酵生产曲梭的研究

分离到Ａｓｐｅｒｇｉｌｌｕｓ ｏｒｙｚａｅ１３个菌株,其曲酸产量变化幅度１６．６－４８．６ｍｇ／ｍｌ,从中选出４个高产菌株。在１％酵母提取物和１５％蔗糖培养液中３０℃发酵培养,８￣１０天菌体生长量和曲酸产量达到最大值,随后曲酸产量迅速下降。蔗糖浓度对菌体生长和曲酸产量影响甚大,最适蔗糖浓度为１５％。天冬氨酸、甘氨酸、赖氨酸、谷氨酸、吡哆醇、叶酸和抗坏血酸有利于菌体生长并显著提高曲酸产量。将在ＹＥＳ     

复合诱变对米曲霉产曲酸的影响

发酵法生产曲酸还未实现大规模工业化生产的原因之一是曲酸菌种产酸率较低,本文以平展米曲霉（Aspergillus oryzae effusus)AS32为出现菌株,经UV和^60Co诱变处理,筛选获得一株高产曲酸变异株AUR163,以葡萄糖为碳源,酵母膏为氮源,32℃摇瓶和30L罐发酵培养4天,产酸达6．8g/100mL。平均生产效率为17．0g/L.d最高可达30．5g/L.d比出发菌AS32提高190％以上,这表明UV和^60Co作诱剂,可以大幅度提高米曲霉的曲酸生产效率。     

曲酸的发酵生成与检测

本文概述曲霉发酵合成曲酸所需的各种营养因素及其对产酸力的影响,发酵工艺与菌种诱变,合成机理,曲酸的鉴定和检测方法,并对发酵工艺的发展趋势提出一些看法。     

曲酸生产菌的诱变选育

Ａｓｐｅｒｇｉｌｌｕｓ ｏｒｙｚａｅ ２３３６两次紫外诱变后筛选出突变苗株ＵＶ２１０１２－１。该菌株曲酸产量比出发菌提高了１．６８倍;遗传性状稳定,传代５次曲酸产量基本不下降,而且发酵周期也比出发菌株明显缩短。     

曲酸生产菌的诱变选育

Aspergillusoryzae2336经两次紫外诱变后筛选出突变菌株UV21012-1。该菌株曲酸产量比出发菌株提高了1．68倍;遗传性状稳定,传代5次曲酸产量基本不下降,而且发酵周期也比出发菌株明显缩短。     

曲酸的发酵生产及其应用的研究

筛选了１１８株曲霉、获得一株黄曲霉８００４。采用葡萄糖与蛋白胨为主要原料,８００４菌株发酵产曲酸４％以上。发酵液通过过滤、浓缩可直接结晶。利用发酵方法制得的曲酸与硬脂酸进行酯化反应,生成曲酸硬脂酸双酯、收率达８０％以上。化妆品试验表明曲酸及曲酸硬脂酸酯具有增白与防晒作用。曲酸（ｋｏｊｉｃ ａｃｉｄ）化学名称５－羟基,２－羟甲基ｒ－吡喃酮,１９０７年斋滕在米曲抽提液中发现（１）。１９９２年确定其结构     

米曲霉(Aspergillus oryzae)FSO179产α-淀粉酶固体发酵优化的研究

米曲霉(Aspergillus oryzae)FSO179产α-淀粉酶固体发酵优化结果表明:最佳有机碳源为玉米粉,最佳有机氮源为花生饼粉;培养基正交试验表明最佳培养基配方为:花生饼粉20%,玉米粉5%,无机盐为c组配方;初始发酵pH为7.4;最适的发酵温度为33℃;在以上最适条件下固体培养6d,发酵产酶水平可达1300.6u/g,优化结果比初始设计提高了42.9%。该酶酶学特性研究表明:该酶作用的最适温度为55℃;最适作用pH为4.0;Fe2 、Ba2 、Cu2 、Mn2 、Fe3 金属离子对酶具较强抑制作用,而Ca2 对酶具有一定激活作用。     

曲酸的发酵生成与检测(综述)

本文概述曲霉发酵合成曲酸所需的各种营养因素及其对产酸力的影响,发酵工艺与菌种诱变,合成机理,曲酸的鉴定和检测方法,并对发酵工艺的发展趋势提出一些看法。     

酿酒用米曲霉制曲条件的研究

研究了不同翻曲次数、接种量、培养温度、培养时间下米曲霉的酶活特性。根据单因素试验结果进行培养条件的优化。研究表明酿酒用米曲霉酶活力最佳的培养条件为:以大米为原料,装量30g、接种量4%、温度35℃、培养78h,每间隔24h进行翻曲。     

米曲霉发酵纯化无患子皂苷的工艺研究

采用微生物发酵法对无患子皂苷水提取液进行纯化.比较了采用自然发酵、接种酵母菌发酵和接种米曲霉发酵纯化无患子皂苷的效果.结果表明,提取液不灭菌,接种米曲霉发酵纯化效果较为明显,优化后的发酵条件为:温度30℃、接种龄12 h、接种量为3％、摇床转速150 r/min,发酵7d后,皂苷含量稍有下降,但皂苷纯度可从48.71％提高到82.47％.米曲霉发酵法明显优于水提醇沉法、絮凝法和正丁醇萃取法.     

Aspergillus oryzae laeA Regulates Kojic Acid Synthesis Genes

Kojic acid synthesis genes regulation was investigated in Aspergillus oryzae. Our results indicate that kojic acid production was lost in the laeA disruption strain, but was recovered in the LaeA complement strain. Real-time PCR also confirmed that expression of kojic acid biosynthesis genes decreased in the laeA disruption strain, indicating that these genes are under the control of LaeA.     

Invasion of paranasal sinuses by Aspergillus oryzae

A 24-year-old male patient receiving chemotherapy for acute promyelocytic leukemia developed fever, right periorbital swelling and mild right proptosis. A head scan showed opacification of the right maxillary and ethmoid sinuses with adjacent soft tissue swelling. Biopsy of the nasal mucosa demonstrated the typical septate hyphae of Aspergillus species which was later shown on culture to be Aspergillus oryzae. A. oryzae has only rarely been reported in human disease and there is confusion as to its precise identification and role. We would like to confirm the pathogenicity of A. oryzae with this uncommon presentation of aspergillosis and also emphasize the need to take adequate and multiple cultures in suspected cases so that the possibility of species identification will be maximized.     

Aspergillus oryzae nrtA affects kojic acid production

We analyzed the role of the nitrate transporter-encoding gene (nrtA) of Aspergillus oryzae by gene disruption. Southern hybridization analysis indicated that homologous recombination occurred at the resident nrtA locus. Real-time PCR showed that the nrtA gene was strongly inducible by NaNO₃. The nrtA disruptant did not exhibit normal growth when nitrate was available as the sole nitrogen source. These results indicate that NrtA is essential for nitrate uptake in A. oryzae. Kojic acid (KA) production was inhibited by the addition of a small amount of sodium nitrate. The nrtA-disrupted strain was deficient in the uptake of nitrate. As a result, KA production in this strain was not considerably affected by the presence of nitrate.     

Cultivation characteristics of immobilized Aspergillus oryzae for kojic acid production

Aspergillus oryzae in situ grown from spores entrapped in calcium alginate gel beads was used for the production of kojic acid. The immobilized cells in flask cultures produced kojic acid in a linear proportion while maintaining the stable metabolic activity for a prolonged production period. Kojic acid was accumulated up to a high concentration of 83 g/L, at which the kojic acid began to crystallize, and, thus, the culture had to be replaced with fresh media for the next batch culture. The overall productivities of two consecutive cultivations were higher than that of free mycelial fermentation. However, the production rate of kojic acid by the immobilized cells was suddenly decreased with the appearance of central cavernae inside the immobilized gel beads after 12 days of the third batch cultivation.     

米曲霉M-4降解己烯雌酚的条件优化

【目的】以米曲霉(Aspergillus oryzae)M-4对己烯雌酚(Diethylstilbestrol,DES)的降解率为响应值,对其降解条件进行优化。【方法】采用Plackett-Burman法对培养基组分和降解条件筛选显著性影响因素,并通过Box-Bohnken设计试验优化降解条件。【结果】最优培养基配方为:蛋白胨1.3%,CaCl_2 0.045%,葡萄糖0.5%,K_2HPO_4 0.15%,KH_2PO_4 0.05%,NaCl 0.05%,Tween 80 0.2%,DES质量浓度44 mg/L;最优培养条件为:初始p H 7.5,种龄72 h,转速140 r/min,培养温度28°C,培养时间72 h。【结论】在最优条件下菌株M-4对DES降解率为83.89%,比优化前(60.98%)提高1.38倍,差异极显著(P0.01)。