不同产纤维素酶菌种特定底物培养产酶活力比较

纤维素酶是由几种不同酶组成的复合酶系,由于酶催化反应底物的复杂性,从不同霉菌和不同底物发酵分离得到的纤维素酶组分和酶活力有着很大差别.本论文的主要目的主要是针对不同底物和不同霉菌进行产纤维素酶活力比较评价.实验选用CGMCC3.3002 和CICC13048 两种菌,使用液体发酵法在微晶纤维素和糠醛渣两种底物上进行产酶培养,在特定的时间测定其产的纤维素酶的纤维二糖酶活力、内切葡聚糖酶活力、外切葡聚糖酶活力以及滤纸酶活.产滤纸酶活比较高的菌株CGMCC3.3002,以糠醛渣为特定底物的滤纸酶活要高于微晶纤维素特定底物,且CGMCC3.3002 在微晶纤维素和糠醛渣底物的酶活力差异较大,该菌株可通过紫外诱变使其酶活力更高,有望用于糠醛渣生产燃料乙醇的过程中.     

维生素C二步发酵的新组合菌系

以掷孢酵母作为伴生菌与氧化葡萄糖酸酐菌组成新混菌体系,对其产酸性能和特点进行了研究。实验室摇瓶结果显示,新菌系混菌状态不同,产酸不同,以KGA含量为4．8,小菌／掷孢酵母为31：1种液接种时,最有利于产酸,增加接种生物量可提高产酸速度,缩短发酵周期,但不影响最终产酸量,相同条件下,新菌系产酸能力高于现有菌系,酸量增加5mg/ml-7mg/ml,发酵周期缩短6h-8h,酸转经率提高3％4－％,最高产酸点PH值下降约0．5,表现出较大的产酸潜力和可修饰性。     

大豆蛋白复合酶解产物在促微生物生长和发酵中的初步应用研究

为探讨大豆蛋白复合酶解产物在促微生物生长和发酵中的可行性,利用2709碱性蛋白酶和中性纤维素酶复合酶解大豆蛋白,酶解产物经干燥、粉碎后添加到培养基中,通过接种微生物观察其生长状况和发酵情况表征效果。研究发现,大豆蛋白复合酶解产物可以促进微生物生长和发酵产酶,试验结论为微生物培养提供了新的代谢资源。     

以掷孢酵母作为伴生菌产生VC前体KGA的研究

以掷孢酵母作为伴生菌与氧化葡萄糖酸杆菌组成新混菌体系,通过测定生长代谢曲线,对其产酸性能和特点进行了研究。结果表明：相同条件下,新菌系产酸能力高于现有菌系,酸量增加5-7mg/ml,发酵周期缩短6-8h,酸转化率提高3-4%,最高产酸点pH值下降约0.5个单位,表现出较大的产酸潜力和可修饰性。     

四川浓香型与酱香型酒曲细菌区系构成的比较研究

浓香型酒和酱香型酒,不仅发酵制酒的工艺各异,而且制曲工艺也不同。由于制曲工艺的不同,因而影响到两大类酒曲中微生物区系的组成。本文报道将酒曲中的细菌分为三大类群:产酸细菌;底物分解细菌;放线菌,并进行了计数,研究了它们数量组成与结构特征。讨论了这些细菌与两大类型酒风格形成的关系。     

南海局部海洋沉积物中真菌多样性及产酶活性

【目的】从11份南海海洋沉积物中分离耐盐真菌,并对其物种多样性及产酶活性进行研究。【方法】利用平板涂布法分离耐盐真菌,基于形态学和ITS序列的系统进化研究耐盐真菌多样性;利用6种筛选培养基对耐盐真菌进行产酶活性筛选。【结果】分离得到1689株耐盐真菌,共41个形态种。形态学和ITS序列分析表明,这些真菌归于15个属,其中曲霉属(Aspergillus)和青霉属(Penicillium)为优势菌群。对已测序的41株耐盐真菌的产酶活性研究表明,8株产纤维素酶,9株产淀粉酶,5株产复合酶,16株产蛋白酶,3株产脂肪酶,未发现产壳聚糖酶的菌株,其中Acrodontium sp.8m和Aspergillus sp.86b产复合酶的活性相对较高,而Penicillium sp.41m产蛋白酶的活性相对较高。【结论】南海局部海洋沉积物中耐盐真菌丰富,多数菌株具有产酶活性。     

高产复合酶菌株HD-1选育的研究

从产果胶酶的黑曲霉(Aspergillus niger)菌中分离出一支产酸性蛋白酶等多种水解酶的菌株No．3号。经铜蒸汽激光诱变,选育出一支高产复合酶的菌株FID-1,该菌在简单的固体发酵培养基上,28℃培养48hr,每克鲜曲的酶活力(U)为：酸性蛋白酶7500u、纤维素Cx 酶 9061U、纤维素CL酶3581U、果胶酶5471U、糖化酶5582U。酶活平均提高率为38.86％,最高幅度是78.6％。该菌经多次连续传代和贮存一年后,产酶性状稳定。该菌株是目前国内饲料用酶制帮生产株中,酶系最齐全,产酶水平位于前列的优良菌株。     

羊毛生物整理复合酶高产菌的激光选育*

采用激光对宇佐美曲霉棕色突变株W25进行诱变处理。选育到一株产酸性蛋白酶、纤维素CMC酶的复合酶生产菌L86,与出发菌株相比发酵单位酸性蛋白酶提高了42.7%、纤维素CMC酶提高了40.9%。所选育的L86经多次传代,遗传性状非常稳定。生物整理试验表明,L86复合酶比较适合用作羊毛织物生物整理用酶。     

羊毛生物整理复合酶高产菌的激光选育

采用激光对宇佐美曲霉棕色突变株W25进行诱变处理。选衣到一株产酸性蛋白酶、纤维素CMC酶的复合酶生产菌L86,与出发菌株相比发酵单位酸性蛋白酶提高了42．7％、纤维素CMC酶提高了40．9％。所选衣的L86经多次传代,遗传性状非常稳定。生物整理试验表明,L86复合酶比较适合用作羊毛织物生物整理用酶。     

不同小麦品种（系）对麦长管蚜的抗性

采用网罩麦长管蚜Sitobion miscanthi (Takahashi)的观测方法,对15个不同抗性小麦品种（系）进行苗期不选择性、抗生性测定;选择其中5个代表性品种（系）观测了田间扬花期麦长管蚜的产蚜量,测定了小麦旗叶和穗部中单宁与槲皮素的含量以及麦长管蚜羧酸酯酶（CarE）与谷胱甘肽S-转移酶（GST）的活性。结果表明,代表性品种（系）在苗期对麦长管蚜的产蚜量的影响与扬花期的呈显著正相关（r＝0.956*）。穗部槲皮素的含量与不同抗性品种（系）上的产蚜量呈显著负相关（r＝-0.941*）;单宁含量在不同抗性品种（系）间存在显著差异,其含量变化与产蚜量无显著相关。取食不同抗性品种（系）后麦长管蚜的CarE和GST酶活力存在显著差异。结论认为小麦不同品种（系）对麦长管蚜产蚜量（生殖力）的抑制作用是其抗蚜的重要特性,尤其是中4无芒和冀保一号对麦长管蚜抗生性较强。     

N+注入选育黑曲霉益生菌及其突变菌株产酶条件的研究

以益生菌株黑曲霉AN01为材料,经N 多次诱变得突变益生菌株AN03。结果表明,出发益生菌株AN01酸性蛋白酶、纤维素酶和果胶酶的酶活分别由原来的71.6Ug、141.7Ug和264.8Ug相继提高到996.5Ug、940.4Ug和906.5Ug。突变益生菌株AN03经传5代培养,产酶特性稳定。试验还研究了变突变益生菌株AN03最佳产酶条件,培养基为每升含麸皮105g,玉米芯105g,豆粕105g,氯化铵16g,pH5.0。30℃培养4d。     

Screening and mutagenesis of Aspergillus niger for the improvement of glucose 6-phosphate dehydrogenase production

The strain of Aspergillus niger ZBY-7 was selected as the original strain of glucose 6-phosphate dehydrogenase production. After mutagenesis of the strain using UV irradiation and nitrosoguanidine, mutants of Aspergillus niger resistant to certain metabolic inhibitor were obtained. Five of the mutants showed increased glucose 6-phosphate dehydrogenase production. The mutant resistant to antimycin A (Aspergillus niger AM-23) produced the highest level of glucose 6-phosphate dehydrogenase (695.9% of that from the original strain).     

黑曲霉产菊粉酶菌株的选育及培养基优化

为获得高产菊粉酶的黑曲霉菌株,以Aspergillus niger YH-1为出发菌株,经过亚硝基胍(NTG)诱变,以高温高菊芋粉相结合的方式进行梯度驯化,选育出一株产菊粉酶菌株YH-3,并运用响应面实验方法对该菌株的培养基进行优化。确定了最佳培养基组成:菊芋粉25.2 g/L、豆饼粉40 g/L、蔗糖酯4.9 g/L、NaCl 5.5 g/L。发现内切菊粉酶活力(I)由60.9 U/mL提高到165.0 U/mL,比出发菌株提高了1.7倍。研究证明蔗糖酯对于黑曲霉YH-3发酵产菊粉酶是一种有效的促进剂。     

制霉菌素抗性筛选高活性苎麻脱胶菌诱变菌株

利用制霉菌素抗性筛选高渗透性突变株,提高黑曲霉菌对苎麻纤维的脱胶能力,使微生物脱胶能用于工业生产实践之中.分别用紫外线、硫酸二乙酯、亚硝酸作为诱变剂对黑曲霉3.0.2菌株进行诱变处理.以制霉菌素抗性为遗传标记,从突变菌株中定向筛选得到一株高活性苎麻脱胶菌黑曲霉3.0.2-26.在以未经刮制的苎麻韧皮为主要碳源,0.7%(NH_4)_2SO_4为氮源,添加00.5%KCl;00.5%MgSO_4;0.1%K_2HPO_4; 0.1%酵母膏;Tween80 0.1%的培养液中,接入黑曲霉3.0.2-26,置30℃下,150 r/min处理30 h左右,脱胶苎麻纤维的残胶率平均为14.43%.     

植酸酶产生菌黑曲霉N14的诱变选育及其基因分析

以植酸酶产生菌黑曲霉03214为出发菌株,经紫外线和亚硝基胍诱变,获得了产酶活性较出发菌株提高了22．3％,达422IU／ml发酵液的突变菌株黑曲霉N14,其最适pH值为2．5,最适温度为50℃。通过对黑曲霉N14植酸酶phyA基因进行PCR扩增,获得了一条长约1．5kb的特异性产物。以pMD18-T为载体,构建了含有目的基因片段的重组质粒。DNA序列测定表明,目的基因片段含有植酸酶phyA基因的完整序列(GenBank Accession：AY426977),phyA基因全长1506bp,其中包含一段长102bp的内含子,编码467个氨基酸,有10个潜在的糖基化位点,5’端有一编码19个氨基酸的信号肽序列。实验结果为植酸酶基因工程菌的构建奠定了基础。     

Isolation and evaluation of tannin-degrading fungal strains from the Mexican desert

Eleven fungal strains (4 Penicillium commune, 2 Aspergillus niger, 2 Aspergillus rugulosa, Aspergillus terricola, Aspergillus ornatus and Aspergillus fumigatus) were isolated, characterized morphologically and by their capacity to degrade tannins. Aspergillus niger Aa-20 was used as control strain. Several concentrations of hydrolysable tannin (tannic acid) were used as sole carbon source. All strains were able to degrade hydrolysable tannins. Aspergillus niger GH1 and PSH showed the highest tannin-degrading capacity (67 and 70%, respectively). Also, the fungal capacity to degrade condensed tannin (catechin) was tested. Aspergillus niger PSH and Penicillium commune EH2 degraded 79.33% and 76.35% of catechin. The results demonstrated the capacity of fungi to use hydrolysable and condensed tannins as carbon source.     

黑曲霉mnn9基因缺失株的构建及其功能分析

本研究通过分析比较黑曲霉基因组与酿酒酵母基因组序列同源性,分离鉴定了黑曲霉mnn9基因。通过同源重组,在黑曲霉GICC2773(ΔAP4:pGPT-laccase)菌株中敲除了mnn9基因。该黑曲霉mnn9基因缺失使外源蛋白漆酶的分泌表达提高了14%,内源蛋白葡萄糖淀粉酶的分泌表达则降低了4%。     

一株具有拮抗作用的解淀粉芽孢杆菌的筛选、鉴定及生物学特性研究

本研究以樱桃番茄成熟红果为样本,以极细链格孢菌为指示菌筛选得到一株对番茄采后病原菌有抑制作用的菌株KL-1。通过平板拮抗试验研究了菌株KL-1对番茄采后常见病原真菌极细链格孢菌、黑曲霉、青霉菌、尖侧多隔孢霉、拟康宁木霉、盐生枝孢霉、子囊菌、胶孢炭疽菌等八种病原菌的抑制作用,同时通过形态学、生理生化及16S rDNA分子生物学特征对菌株进行了鉴定,并对其基本生物学特性进行了研究。结果表明:菌株KL-1对于七种病原菌极细链格孢菌、黑曲霉、青霉菌、拟康宁木霉、盐生枝孢霉、子囊菌和胶孢炭疽菌均有明显的抑制作用,其中对黑曲霉的抑制率最大为81%,对其他六种病原菌抑制率也均高于70%,对尖侧多隔孢霉的抑制率为0,说明菌株KL-1可以抑制番茄多种常见病原真菌,具有开发为生防制剂的潜力。经鉴定KL-1为解淀粉芽孢杆菌(Bacillus amyloliquefaciens);该菌培养9 h内生长最旺盛,最适生长pH为7.0,最适生长温度为37℃。     

Characterization of a polyketide synthase in Aspergillus niger whose product is a precursor for both dihydroxynaphthalene (DHN) melanin and naphtho-γ-pyrone

The genome sequencing of the fungus Aspergillus niger uncovered a large cache of genes encoding enzymes thought to be involved in the production of secondary metabolites yet to be identified. Identification and structural characterization of many of these predicted secondary metabolites are hampered by their low concentration relative to the known A. niger metabolites such as the naphtho-γ-pyrone family of polyketides. We deleted a non-reducing PKS gene in A. niger strain ATCC 11414, a daughter strain of A. niger ATCC strain 1015 whose genome was sequenced by the DOE Joint Genome Institute. This PKS encoding gene we name albA is a predicted ortholog of alb1 from Aspergillus fumigatus which is responsible for production of the naphtho-γ-pyrone precursor for the 1,8-dihydroxynaphthalene (DHN) melanin/spore pigment. Our results show that the A. nigeralbA PKS is responsible for both the production of the spore pigment precursor and a family of naphtho-γ-pyrones commonly found in significant quantity in A. niger culture extracts. The generation of an A. niger strain devoid of naphtho-γ-pyrones will greatly facilitate the elucidation of cryptic biosynthetic pathways in this organism.     

Production of fungal biomass protein using microfungi from winery wastewater treatment

This study was carried out to investigate the production of fungal biomass protein (FBP) in treatment of winery wastewater using microfungi. Three fungal strains, Trichoderma viride WEBL0702, Aspergillus niger WEBL0901 and Aspergillus oryzae WEBL0401, were selected in terms of microbial capability for FBP production and COD reduction. T. viride appeared to be the best strain for FBP production due to high productivity and less nitrogen requirement. More than 5 g/L of fungal biomass was produced in shake fermentation using T. viride without nitrogen addition, and by A. oryzae and A. niger with addition of 0.5-1.0 g/L (NH4)2SO4. The FBP production process corresponded to 84-90% COD reduction of winery wastewater. Fungal biomass contained approximately 36% protein produced by two Aspergillus strains, while biomass produced by T. viride consisted of 19.8% protein. Kinetic study indicated that maximum fungal cell growth could be achieved in 24h for T. viride and 48 h for A. oryzae and A. niger. Current results indicated that it could be feasible to develop a biotechnological treatment process integrated with FBP production from the winery waste streams.