Chemical Destruction of Aspergillus niger Conidiospores

SUMMARY: Destruction of A. niger conidiospores at 20°C (68°F) by 20 ppm NaClO and 20 ppm iodine as iodophor yielded D values of 0.61 min and 0.86, respectively at pH 3.0 and 1.31 and 2.04 min, respectively at pH 7.0. On the basis of mojar concentrations, iodine was slightly more effective than chlorine. A D value of 0.026 min was obtained with 4% NaOH at 60°C (140°F) indicating 4% NaOH at 60°C to be far more germicidal than 20 ppm of either halogen compound at 20°C. One per cent NaOH at 30°C resulted in an immediate and rapid release of amino acids presumably from the spore wall during the first 2 min of contact and a slower rate of release of RNA, with DNA released at the slowest rate.     

Biotransformation of quinazoline and phthalazine by Aspergillus niger

Cultures of Aspergillus niger NRRL-599 in fluid Sabouraud medium were grown with quinazoline and phthalazine for 7 days. Metabolites were purified by high-performance liquid chromatography and identified by mass spectrometry and proton nuclear magnetic resonance spectroscopy. Quinazoline was oxidized to 4-quinazolinone and 2,4-quinazolinedione, and phthalazine was oxidized to 1-phthalazinone.     

黑曲霉菌体制备壳聚糖的工艺研究

研究了黑曲霉不同发酵条件(发酵温度、发酵时间、发酵pH值、摇床转速)对壳聚糖产率的影响。并对培养基组成和培养条件进行了优化试验,结果表明,最佳培养液成分为70mL玉米浆,4g葡萄糖,1.2g硫酸镁,接入8.0×108个/mL孢子;培养条件发酵温度27℃~31℃,发酵时间72h,发酵pH值7.4~7.6,摇床转速130r/min。     

黑曲霉单宁酶发酵工艺

用黑曲霉Aspergilhus niger QG 0301进行单宁酶发酵，制得酶制剂。实验结果表明：Aspergillus niger QG 0301进行单宁酶发酵的适宜培养基包括：混合碳源（或玉米淀粉）、硫酸铵、磷酸二氢钾、碳酸钙、硫酸镁、单宁酸；在30℃、120r/min振荡培养5天，单宁酶产量平均为18．55u／mL。     

Strain-specific polyketide synthase genes of Aspergillus niger

In silico comparison of 34 putative pks genes in Aspergillus niger strain CBS 513.88 versus A. niger strain ATCC 1015 genome revealed significant nucleotide identity (>95% covering a minimum of 99% of the gene sequence) for 31 of these genes (approximately 91%). A. niger CBS 513.88 harbors three putative pks genes (An01g01130, An11g05940, and An15g07920), for which nucleotide identity was not found in A. niger ATCC 1015. To compare the results of the in silico analysis with the in vivo situation, experimental data were obtained for a large number of A. niger strains obtained from different substrates and geographical regions. Three putative pks genes that were found to be variable between the two A. niger strains using bioinformatics tools were in fact strain-specific genes based on experimental data. The PCR amplification signals for the An01g01130, An11g05940, and An15g07920 pks genes were detected in only 97%, 71%, and 26% of the strains, respectively. Southern blot analyses confirmed the PCR data. Because one of the strain-specific pks genes (An15g07920) is located in a putative ochratoxin cluster, we focused our investigation on that region. We assessed the ochratoxin production capability of the 119 A. niger strains and found a positive association between the presence of this pks gene and the capability of the respective strain to produce ochratoxin.     

黑曲霉果胶酶产生条件的初步研究

本文报道了黑曲霉A3.1在麦麸固体培养基的产酶条件,在不同氮源试验中以(NH4)2SO4为最佳,该菌产酶的最佳条件为28℃,含水量45%,起始pH5.0,时间3d.     

黑曲霉菊粉酶的分离纯化与酶学特性

黑曲霉（Asperginusniger）105发酵液经硫酸铵分级沉淀、DEAE-纤维素离子交换层析、Sephadex G-100凝胶过滤,得到菊粉酶组分,纯化倍数为7．73倍,活力回收率为4．39％。该菊粉酶的最适pH值为6．0,最适温度为50℃,Cu^2＋、Mn^2＋、Zn^2＋、Fe^2＋对该酶有很强的抑制作用。菊粉酶活力与蔗糖酶活力之比为16．5,表现为内切酶活性。以菊粉为底物时,米氏常数（Kin）为0．1999 mmol／L,最大反应速度（Vmax）为117．32μmol／（mg·min）。     

黑曲霉原生质体的制备、再生及转化条件

为了建立原生质体介导的黑曲霉转化系统，研究了菌龄、酶系统、渗透压稳定剂、酶解时间对葡萄糖淀粉酶生产菌株黑曲霉CICIMF0410原生质体形成与再生的影响。结果表明，培养4d的幼嫩菌丝体最适于制备原生质体；综合考虑原生质体形成与再生的情况，作者选用1mol／L山梨醇为最适渗透压稳定剂，1g／dL蜗牛酶-1g／dL纤维素酶-0．1g／dL溶壁酶为最适裂解酶组合，30℃酶解2．5～3h，最适合的原生质体的再生培养基为含0．6mol／LMgSO4的TZ培养基。在PEG和CaCl2存在条件下，以潮霉素B为选择性标记，质粒pBC-Hygro转化原生质体，每微克DNA可获得4～5个转化予。     

黑曲霉产木聚糖酶的特性

研究了木聚糖酶产生菌黑曲霉(A.niger)238的产酶特性和麸曲的浸提条件,并对其浸提酶液进行浓缩.结果表明,菌株黑曲霉(A.niger)238产木聚糖酶受诱导物的影响,发酵时间在68～72h期间达到产酶高峰,酶活力为286U/mL.最佳氮源为(NH4)2SO4,装料量为每瓶10g,接种量为每瓶0.3mL.其发酵麸曲用固液比为1∶5的2g/dLCaCl2溶液,30℃浸提1.5h;浸提液采用25℃,40kPa,冷却水温度18℃条件超滤浓缩可获得90%以上回收率.     

黑曲霉产木聚糖酶的研究

筛选了 1株高产木聚糖酶的黑曲霉 (Aspergillusniger)An 2 3 8菌株 ,研究了其在固态培养基中的产酶条件。该菌株发酵曲中除含有木聚糖酶 5 117U /g(干曲 )外 ,还有纤维素酶 42 5U/g(干曲 ) ,果胶酶 12 3 6U/g(干曲 ) ,蛋白酶 2 2 5 3 1U/g(干曲 )。     

糖化黑曲霉复壮方法的研究

采用透明圈法对糖化黑曲霉AS3.324和AS3.4309的复壮方法进行研究,选出了三种适合的筛选培养基,确定了具体的操作步骤.复壮后菌株的麸曲糖化酶活力分别比退化的出发菌株的麸曲糖化酶活力提高45%和44%.     

黑曲霉VVTP84生产果糖转移酶

从产果糖转移酶的 11株菌株中筛选出一株黑曲霉VVTP84菌 .该菌株在含蔗糖的培养基中 ,最佳摇瓶发酵时间为 30h ,pH值为 7.0 ;当蔗糖质量浓度在 2 5 0g/L以内时 ,产酶与蔗糖质量浓度呈正相关 ;MgSO4 ·7H2 O和KH2 PO4 的添加量分别以控制在 1.5 g/L和 1.0 g/L为宜     

米曲霉谷氨酰胺酶在黑曲霉中的重组表达与酶学特性

该研究将米曲霉RIB40（Aspergillus oryzae RIB40）来源的谷氨酰胺酶（GahB）在黑曲霉（Aspergillus niger）宿主中分泌表达。基于该研究所建立表型鉴定板与孔板培养的通量鉴定筛选方法成功得到重组表达谷氨酰胺酶的转化子H-GahB,最高酶活力达到1.35 U/mL。为了增加目的基因在宿主中的拷贝数,采用CRISPR/Cas9基因组编辑技术重新构建高拷贝的谷氨酰胺酶表达菌株C-GahB,其酶活力提高到3.56 U/mL,约为H-GahB的2.64倍。进一步采用ARTP诱变技术对C-GahB进行传统诱变育种,获得了谷氨酰胺酶工程菌株A-GahB,其酶活力提升到4.16 U/mL,比出发菌株C-GahB的酶活力提高了0.17倍。纯化后的重组GahB的比酶活达到40.63 U/mg,最适温度为37 ℃,最适pH值为7.0,其在20~40 ℃及pH值5.5~8.0之间稳定性较好。K+对GahB的酶活力具有激活作用,Zn2+和Mn2+则对GahB的酶活力有较为强烈的抑制作用。当盐质量分数为18%时,GahB表现出35.38%的相对酶活力。该研究第一次在黑曲霉中实现了来源于米曲霉RIB40的谷氨酰胺酶GahB的重组分泌表达,为此后对米曲霉谷氨酰胺酶的研究提供了基础。     

代谢改造黑曲霉合成乙酰氨基葡萄糖

该研究以黑曲霉为底盘细胞,首先敲除N-乙酰氨基葡萄糖（N-acetylglucosamine,GlcNAc）摄取相关转运蛋白ngtA编码基因,获得GlcNAc的吸收利用缺陷型菌株,有利于胞外GlcNAc的积累。在此基础上,通过表达大肠杆菌来源的卤酸脱卤酶样磷酸酶编码基因yqaB,构建黑曲霉GlcNAc的完整合成途径,实现GlcNAc的合成,产量为1.78 g/L。通过共过表达氨基葡萄糖-6-磷酸乙酰转移酶基因gnaA和氨基葡萄糖-6-磷酸合成酶基因gfaA强化GlcNAc合成途径,GlcNAc的合成水平提升至3.64 g/L。为增加GlcNAc合成前体GlcNAc6P的胞内供给,利用RNA干扰技术对乙酰氨基葡萄糖-6-磷酸（GlcNAc6P）分解代谢途径中氨基葡萄糖-6-磷酸脱氨基酶基因nagB和乙酰氨基葡萄糖-6-磷酸脱乙酰酶基因nagA基因表达进行弱化表达,GlcNAc产量进一步提高至4.03 g/L。为减弱黑曲霉糖酵解途径与GlcNAc合成途径竞争共同前体物质果糖-6-磷酸,对磷酸果糖激酶基因pfkA进行弱化表达,GlcNAc的最终产量为4.61 g/L。     

黑曲霉xj菌株发酵液的抗菌活性研究

目的:研究黑曲霉xj菌株发酵液的抗菌谱及抗菌活性的稳定性;方法:以常见的病原细菌作为测试菌株,滤纸片法测定xj菌株发酵液的抑菌谱,通过温度、光照以及pH值的变化测定发酵液中抗菌成分的稳定性;结果:xj菌株发酵液对5种病原细菌均有不同程度的抑菌活性,其中时金黄色葡萄球菌和根癌农杆菌的抑菌效果最好,抑菌圈直径分别达到42.14 mm和38.76mm,发酵液中的抗菌成分对光照稳定,但对温度及pH值不稳定;结论:xj菌株发酵液的抗菌范围较广,提取发酵液的抑菌成分时应尽量在低于80℃以下,pH中性环境中进行.     

黑曲霉泡腾片制备工艺优化

该研究采用粉末直接压片法制备黑曲霉（Aspergillus niger）泡腾片,以崩解时限、pH值、发泡量为评价指标,通过单因素试验和正交试验对黑曲霉泡腾片的工艺参数进行优化。结果表明,黑曲霉泡腾片的最佳制备工艺为酒石酸和碳酸氢钠比例1.00∶1.25、崩解剂添加量70%、黑曲霉孢子粉添加量15%、质量分数为10%的聚乙二醇6000乙醇溶液为润滑剂,添加量为3.15 g/mL,质量分数为2.5%为聚乙烯吡咯烷酮乙醇溶液为粘合剂,添加量为7 g/mL。在此优化条件下所得的黑曲霉泡腾片表面光滑,黏冲不明显,pH值为5.7,且崩解时限（23 s）、发泡量（40.79 mL/g）、硬度（4.3 kg）均符合2015版《中国药典》的规定,在水中可迅速崩解。     

黑曲霉TNA-09中α-葡萄糖苷酶基因敲除的研究

以柠檬酸生产菌黑曲霉TNA—09为原始菌株,通过农杆菌介导的方法,将其α-葡萄糖苷酶基因敲除,得到基因敲除菌株TGA101。对原始菌株黑曲霉TNA-09和基因敲除菌TGA101 α-葡萄糖苷酶活力测定,结果相对于TNA—09菌株,TGA101菌株α-葡萄糖苷酶活力下降61．15％。在柠檬酸发酵试验中表现出相对于黑曲霉TNA-09,TGA101菌株发酵液中异麦芽糖含量降低84．67％,柠檬酸提高2．34％,糖酸转化率提高2．34％。     

Inhibitory effect of Aspergillus niger on the growth of Aspergillus ochraceus and Aspergillus flavus,and on aflatoxin formation

Aspergillus ochraceus and A flavus were grown on synthetic media (SM) supplemented with 50 or 200 ml litre^?1 SM on which A niger had been grown previously ( ‘A niger medium’ = ANM). Controls included SM acidified to pH 6.0 or 4.4, SM diluted with 50 or 200 ml litre^?1 water, and diluted-acidified SM. For both fungi, higher growth inhibition was recorded on ANM-containing SM than in the controls. Aflatoxin formation was markedly inhibited on SM to which 20 ml litre^?1 ANM extract (in methanol/chloroform, 2:1 v) had been added, although the growth of A flavus on that medium was almost the same as that in the control. It is concluded that the inhibitory effect of A niger on the growth of fungi should not be attributed merely to pH reduction, but also, mainly, to metabolites produced by the fungus in the growth medium, even at early stages of its growth.