耐氨固氮的催娩克氏菌的高密度培养研究*

根据耐氨固氮型催娩克氏菌的特点,对其发酵工艺进行了研究。确定了以葡萄糖为碳源,合理搭配适量的氮源及无机盐作为高密度培养的基础培养基;在培养的中后期,添加葡萄糖补充碳源,流加氨水补充氮源,同时将pH值稳定在6.5～6.8之间,通过控制适当的通气量、搅拌速度以维持适当的溶氧水平。培养终止时,NG13/pMC73A的菌数达到600～700×10⁸cfu/mL,与原有工艺相比,菌数提高十倍以上,而培养周期基本相同。     

桑木层孔菌固体培养条件的研究

为了研究不同碳源、氮源、初始pH及培养温度对桑木层孔菌菌丝生长的影响,采用固体平板培养法研究了桑木层孔菌的培养条件,结果表明,该菌在淀粉为碳源时生长速度最快但长势较弱,在以葡萄糖和麦芽糖为碳源时生长速度比淀粉为碳源时稍慢,但长势最好;最适氮源为酵母浸粉;初始pH在5.5－8.0范围内变化时菌丝生长差异不大;培养温度在28－33℃范围内对菌丝生长有明显的促进作用。     

喇叭石蕊共生菌藻液体培养的研究(英文)

对喇叭石蕊共生菌、藻液体培养条件进行了研究。结果表明:共生菌生长在以40g/L肌醇为碳源、2g/LL-谷氨酰胺为氮源、起始pH值为7.0的LB液体培养基中,培养温度为20℃时表现最佳。其共生藻的生长在以160g/L葡萄糖为碳源、1.75g/LNaNO3为氮源、起始pH值为5.0的BBM液体培养基中,培养温度为20℃时表现最佳。     

枯草芽孢杆菌发酵条件优化及其破乳效能

本文对枯草芽孢杆菌在不同碳源、氮源培养基的生长及破乳效能进行了研究, 并通过正交试验对枯草芽孢杆菌的发酵条件进行优化结果表明, 单一碳源葡萄糖和混合碳源葡萄糖 + 液体石蜡的培养基可提高枯草芽孢杆菌的发酵产量; 单一碳源葡萄糖、混合碳源葡萄糖 + 汽油和以硝酸铵 + 酵母膏为氮源的菌液有较高的破乳效能; 在正交试验中, 培养温度对枯草芽孢杆菌的发酵产量影响最大, 其最优组合为: 培养温度25oC, 摇床转数140 r/min, 培养pH值7.0, 接菌量6 mL, 培养时间24 h。摇床转数对枯草芽孢杆菌的发酵产物的破乳效能影响最大, 优化结果为: 培养温度25oC, 摇床转数140 r/min, pH值7.0, 培养时间20 h。     

BA-25菌株碱性纤维素酶产酶条件优化研究

试验研究了分离自烟草调制过程中的产芽孢细菌Bacillussp.BA-25菌株碱性纤维素酶产生的优化条件.结果表明:麸皮是最佳碳源,豆饼粉是最佳的氮源,且当碳氮比为2∶1时产酶活性最高;NaCl和KH2PO4对纤维素酶的合成具有重要作用,其适宜用量分别为0.5%～1.0%和0.1%;培养液的初始pH会极大地影响产酶活性,其最适pH为10.最优化的发酵工艺参数为:种子菌龄为24h,在300mL摇瓶中,装入30mL培养基培养温度为37℃,摇床转速为160r/min,在发酵24h后补充1%的葡萄糖,培养48h,该菌产碱性纤维素酶活力可以达到68.4U/mL.     

正交实验优选光合细菌混合菌群产氢的最佳条件

对光合细菌混合菌群产氢影响因子进行了实验研究。通过单因素实验和正交实验, 系统考察了碳源、氮源、碳源浓度、氮源浓度、初始pH值、光照方式、接种量等因素对产氢量的影响, 实验得出最佳工艺条件为: 采用3号菌群, 碳源为葡萄糖, 碳源浓度为3 g/L, 氮源为尿素, 氮源浓度为9 g/L, 接种量为10%, pH值为8.5, 光照方式为12 h光照-12 h黑暗交替光照, 培养温度为30°C。菌种、碳源、碳源浓度、氮源是影响产氢量的重要因素。     

淡紫拟青霉(Paecilomyces lilacinus)培养条件的优化

以查氏培养基为基础,在碳源、氮源、pH值、温度等单因子条件研究的基础上,采用正交实验对淡紫拟青霉的培养条件进行了优化研究,得到了适合其生长的发酵培养基配方。实验结果表明,以蔗糖为碳源(60g/L),硝酸铵为氮源(1.5g/L),pH5～6,培养温度为30℃时最适合该菌的生长。     

罗伊乳杆菌增殖培养基中碳源氮源的优化

目的提高罗伊乳杆菌的发酵活菌数,以提高发酵产率,降低生产成本。方法采用光电比浊法与活菌计数法,通过单因素试验和正交设计方法对罗伊乳杆菌的增殖培养基的碳源和氮源进行优化,并且绘制优化前后的生长曲线。结果罗伊乳杆菌增殖培养基中最佳的碳源、氮源种类与浓度为葡萄糖2.1%、蔗糖3.0%、牛肉膏1.5%、酵母粉1.4%,最佳的培养时间为10h。结论通过优化罗伊乳杆菌的增殖培养基,提高了发酵产率,降低了生产成本。     

鲍氏层孔菌培养条件的研究

本项研究对分离于野外的鲍氏层孔菌从不同的温度、pH值以及不同的碳源和氮源的营养成分三方面进行室内培养,其结果显示鲍氏层孔菌营养菌丝生长的最适温度为28℃;最佳碳源为甘露醇和葡萄糖;最佳氮源为蛋白胨,其次为牛肉膏;而pH值在6.0-8.0的范围内变化对其菌丝体生长影响不大。这些结果为将来大规模人工培植鲍氏层孔菌提供了很好的指导作用。     

粗毛纤孔菌的生物学特性和抗氧化活性研究

以野外分离的一种药用真菌粗毛纤孔菌Inonotus hispidus为研究对象,对其生物学特性与抗氧化活性进行了研究。通过改变培养温度、初始pH、碳源及氮源4个单因素对粗毛纤孔菌进行固体培养,结果表明,最适培养温度为30℃、初始pH为9.0、碳源为蔗糖、氮源为酵母浸粉;采用L₉(3³)三因子三水平正交试验对固体培养最适碳源含量、氮源含量及初始pH组合进一步研究,得出对粗毛纤孔菌丝长速的影响排序为：氮源含量>碳源含量>初始pH,最佳组合为蔗糖30g/L、酵母浸粉1 g/L、初始pH 10.0。同时测定了粗毛纤孔菌在液体培养时的抗氧化活性,结果发现,粗毛纤孔菌液体培养的14 d内,多酚黄酮含量始终维持在较高的水平,对羟自由基、DPPH自由基、ABTS自由基的清除能力和铁离子还原能力较强,表明粗毛纤孔菌具有一定的抗氧化活性。     

桉树与联合固氮菌相互作用的研究

联合固氮菌-催娩克氏菌（Klebsiella oxytoca NG13/pMC73A)接种木栖植物桃金粮种（Myrtaceae)桉树属（Eucalyptus)的苗木,研究它们之间相互作用关系。扫描电镜观察结果表明;联合固氮菌不但可以在桉树根表定殖,而且还可进入根内定殖,并在接种桉树的根际,根表和根内均分离到该菌,接种联合固氮菌能刺激桉树根系的分泌作用,并对根系分泌物的氨基酸,糖及激素的含量有所影响,联合固氮菌对桉树生长有明显的促进作用。     

The use of purine compounds as sole sources of carbon and nitrogen by Klebsiella species

Sixty-one strains of Enterobacteriaceae were tested for purine assimilation, including twenty-five Klebsiella pneumoniae, seventeen K. oxytoca and nineteen others. Only K. pneumoniae and K. oxytoca were able to use guanosine triphosphate, xanthine, hypoxanthine, or uric acid as sole sources of carbon and nitrogen. When guanosine triphosphate was used as sole source of nitrogen and carbon, the lag phase was prolonged. The addition of glucose did not affect the maximum number of viable cells for K. pneumoniae ATCC 29665, but produced an increase for strain K. oxytoca ATCC 13030. In the case of uric acid, ATCC 29665 had a more distinct lag phase of growth than ATCC 13030. Apart from this, they appeared to be very similar. On solid chemically defined GTP medium, some strains of Klebsiella were able to produce a water-soluble brown pigment.     

Effect of inoculation withKlebsiella oxytoca andEnterobacter cloacae on dinitrogen fixation by rice-bacteria associations

The influence ofKlebsiella oxytoca andEnterobacter cloacae inoculation on dinitrogen fixation by the rice-bacteria association was examined in pots in a greenhouse. For inoculation,K. oxytoca NG13 isolated from a Japan paddy soil,E. cloacae E26 isolated from a China soil and following three strains were employed.K. oxytoca NG1389 is a mutant from NG13 and has no nitrogenase activity (nif). K. oxytoca NG13/pMC71A andE. cloacae E26/pMC71A were produced by inserting anif A containingK. pneumoniae plasmid (pMC71A) to NG13 and E26, respectively. These two strains were able to fix dinitrogen fixation in the presence of ammonium, whereas nitrogenase activity of wild strains (NG13 and E26) were repressed under this condition. Inoculation effects were tested on two rice (Oryza sativa L.) varieties, a Indica type C5444 and a Japonica type T65. Rice seedlings were planted to nonsterilized potted soil, and grown under flooded conditions. Upon inoculation with NG13 and E26, growth and N increment of plants particularly in T65 were stimulated above NG1389 inoculated plants. Assay by¹⁵N dilution and acetylene reduction techniques indicated that this N increment may be due to fixed N. Inoculation with NG13/pMC71A and E26/pMC71A resulted in more dry weight and fixed N than those of NG13 and E26 inoculated plants. Dr Y. Hirota died on 23 December 1986.     

葡萄糖3-脱氢酶产生菌的筛选和产酶培养

从土壤中筛选分离得到1株葡萄糖3-脱氢酶产生菌,经生理生化初步鉴定为产酸克雷伯菌(Klebsiella oxyto-ca)。将菌株D8进行产酶优化培养,经过单因素法确定优化培养条件:乳糖为C源,酵母膏为N源,250 mL摇瓶装液量为50 mL,培养基的初始pH为7,33℃培养时G3DH酶比活力最高,达到1.45 U。     

chiA基因在稻根联合固氮菌E26和NG13中的表达

将带有粘质沙雷氏菌几丁质酶基因 (chiA)的 1 8kbHinfⅠ片段分别克隆到表达载体pKK2 2 3 3和质粒pMC71A上 ,构建成几丁质酶表达质粒pKChiA和pMChiA。将这 2种质粒转化稻根联合固氮菌阴沟肠杆菌E2 6 (EnterobactercloacaeE2 6 )和催娩克氏菌NG1 3 (Klebsiellaoxy tocaNG1 3 ) ,chiA基因在这 2菌株中获得高效表达。对表达产物的细胞定位测定表明 ,几丁质酶不仅存在于细胞周间质和胞内 ,而且还分泌到培养物上清液中。在对数生长后期 ,胞外、胞间质和胞内的几丁质酶活性分布分别为 2 3 %～ 2 8%、45 %～ 5 1 %和 2 1 %～ 3 2 %。经SDS 聚丙烯酰胺凝胶电泳检测表明 ,表达的几丁质酶蛋白分子量为 5 8kD。在受体细胞内 ,质粒pMChiA的稳定性要比质粒pKChiA高。     

Short Communication: Optimization of bioprocess conditions for exopolysaccharide production by Klebsiella oxytoca

Optimization of bioprocess conditions increased exopolysaccharide production by a strain of Klebsiella oxytoca from 6g/l to 15g/l; this corresponded to an increase in medium viscosity from 36cP at 12s–1 to 20,000 cP at 0.6 s–1. A combination of equal proportions of tryptone nitrogen and urea nitrogen proved to be the best nitrogen source. Lactose was shown to be the preferred carbon source. At an optimum temperature of 25°C, a pH of 7 was found to be the best for exopolysaccharide production. The concentration of exopolysaccharide produced on whey, enriched whey, enriched whey permeate and lactose-rich medium was comparable.     

Peroxidase production by carbon and nitrogen sources fed-batch culture of Arthromyces ramosus

Summary Carbon and nitrogen sources were investigated for improving peroxidase production by Arthromyces ramosus, a hyperproducer of peroxidase. Glucose as carbon source and a mixture of yeast extract and polypeptone at the ratio of 3 to 5 as nitrogen source in a production medium were shown to give the highest peroxidase activity. During the culture amino acids such as alanine, arginine, methionine, leucine, tyrosine and tryptophan were depleted. Therefore, glucose supplemented nitrogen source fed-batch culture was carried out and a peroxidase activity of 73 U/ml was obtained. This activity was 1.7 times higher than that of glucose fed-batch culture. This indicates that an adequate nitrogen source supply during the culture is effective for improving the peroxidase production by A. ramosus.     

Hemolytic activity of Klebsiella pneumoniae and Klebsiella oxytoca

We demonstrated that Klebsiella pneumoniae and Klebsiella oxytoca possess a selective haemolytic activity on rabbit erythrocytes. Thirty one Klebsiella strains (18 strains of K. pneumoniae and 13 strains of K. oxytoca) were isolated from hospitalized patients. The liquid (Trypcase-soy broth--TSB) and solid (Trypcase-soy agar--TSA) medium, containing the red cells were used for the tests. All the screened strains showed a haemolytic effect on rabbit erythrocytes, provided that the supernatants of the cultures were preincubated with beta-mercaptoethanol or calcium chloride. There was no human and sheep erythrocyte lysis.     

冰核真菌胞外冰核产生条件、成冰生物学特性及其分离纯化的研究*

果糖和葡萄糖作碳源、硫酸铵作氮源、培养温度25℃以下、培养液初始pH5～7和少量通气都利于胞外冰核产生,最佳培养时间受培养温度和接种菌龄的制约,而低温处理、光照及添加丝裂霉素C和HNPA对胞外冰核产生无明显影响。胞外冰核耐热(40℃处理后仍保持较高活性),酸碱适应性强(pH2～13);温度50℃以上、蛋白酶K和高浓度脲处理可完全失活或严重破坏其冰核活性,表明蛋白是真菌胞外冰核的必需成分;胞外冰核溶液中盐浓度高于50mmol/L时,活性才受抑制。25%冰乙醇可有效沉淀真菌胞外冰核,同时又保持较高活性;分离纯化的初步研究显示真菌胞外冰核分子量很大,电荷组成和分布上不均一,所带净电荷为负。本研究加深了对真菌胞外冰核的认识,为进一步分离纯化奠定了基础。     

Fermentation and evaluation of Klebsiella pneumoniae and K. oxytoca on the production of 2,3-butanediol

Klebsiella is one of the genera that has shown unbeatable production performance of 2,3-butanediol (2,3-BD), when compared to other microorganisms. In this study, two Klebsiella strains, K. pneumoniae (DSM 2026) and K. oxytoca (ATCC 43863), were selected and evaluated for 2,3-BD production by batch and fed-batch fermentations using glucose as a carbon source. Those strains' morphologies, particularly their capsular structures, were analyzed by scanning electron microscopy (SEM). The maximum titers of 2,3-BD by K. pneumoniae and K. oxytoca during 10 h batch fermentation were 17.6 and 10.9 g L(-1), respectively; in fed-batch cultivation, the strains showed the maximum titers of 50.9 and 34.1 g L(-1), respectively. Although K. pneumoniae showed higher productivity, SEM showed that it secreted large amounts of capsular polysaccharide, increasing pathogenicity and hindering the separation of cells from the fermentation broth during downstream processing.