表面活性剂对热带假丝酵母降解十六烷的影响

研究了Triton X-100、鼠李糖脂二糖脂(di-RL)和CTAB等3种表面活性剂对1株热带假丝酵母菌株Candida tropicalis降解十六烷的影响.结果表明,低浓度的Triton X-100对菌的生长及其十六烷的降解无明显影响,而高浓度的Triton X-100则抑制菌的生长及其对十六烷的降解,96h后Triton X-100浓度分别为0, 0.1, 0.3, 0.5, 1.0和3.0CMC时,对应的十六烷的平均残留率分别为20.5%, 20.2%, 22.0%, 54.4%, 71.2%和68.8%.di-RL促进菌的生长及十六烷的降解,且促进作用随着di-RL浓度的增加而增大,96h后浓度为0.1, 0.3, 0.5, 1.0和3.0CMC的di-RL分别促使十六烷的平均残留率降低到17.4%, 16.6%, 9.9%, 8.8%和7.8%;di-RL在发酵过程中被降解,且添加的di-RL的浓度越大,其被降解的比例越大.CTAB完全抑制菌体的生长和十六烷的降解,表明其具有毒性作用.     

酵母Candida krusei对合成染料的脱色

通过筛选实验,从土壤中新分离到1株对活性艳红K-2BP具有明显脱色效果的酵母菌株Y-G-I,经鉴定为克鲁斯假丝酵母Candida krusei．该菌株对含活性艳红K-2BP起始浓度为200mg／L的培养基,最大脱色率为99％,达到最大脱色率的时间是12h．克鲁斯假丝酵母的最佳接种量应不低于5％（体积分数）,培养基最适pH在4～9之间,氮源（NH4）2S04浓度不低于0．1％,相对应的碳源葡萄糖浓度不低于0．5％．对脱色机理的研究表明,该菌株对活性艳红K-2BP的去除属于降解脱色．此外,该菌株对另外9种染料（50mg／L）的脱色率在62％～96％之间．其中,对偶氮染料弱酸艳红B、活性黑KN-B和活性红M-3BE的脱色率都达到了90％以上,对三苯甲烷染料（酸性媒介漂蓝B）的脱色率达到了93％．表明克鲁斯假丝酵母在染料废水的处理上可能具有较好地应用潜能．     

双菌种协同代谢酚类化合物的机制研究

以恶臭假单胞菌和热带假丝酵母为对象,进行了苯酚、间甲酚和4-氯酚的生物降解实验,研究了2种菌的纯培养和混合培养方式下3种酚的降解特性和代谢机制.结果表明,当苯酚、间甲酚和4-氯酚的初始浓度分别为100、50和60 mg.L-1时,相对于纯培养,混合培养的动力学常数k的绝对值分别提高了19.0%、2.6%和46.4%.苯...     

Isolation of a novel yeast strain Candida digboiensis TERI ASN6 capable of degrading petroleum hydrocarbons in acidic conditions

A novel yeast species Candida digboiensis TERI ASN6 was isolated from soil samples contaminated with acidic oily sludge (pH 1–3) from the Digboi refinery (Northeast India). The strain TERI ASN6 could degrade 73% of the total petroleum hydrocarbons present in the medium at pH 3 in a week. This strain presents a dimorphic behaviour and showed mycelia morphology when grown under stressed conditions such as low pH and in a medium containing petroleum hydrocarbons. The C. digboiensis strain could efficiently degrade the aliphatic and aromatic fractions of the acidic oily sludge at pH 3 as confirmed by gas chromatography. During the growth of TERI ASN6 in dibenzothiophene (DBT), DBT-sulfone and biphenyl-2-ol were detected. An active cytochrome P450 system, implicated in hydrocarbon oxidation, was also detected in this yeast using degenerated primers based on its conserved regions. This yeast is a potential candidate for petroleum bioremediation treatment of hydrocarbon contaminated acidic soils. Its physiological behaviour allows the strain to work efficiently where other hydrocarbon-degrading bacteria may not survive.     

高浓度苯酚降解菌Candida tropicalis Z-04的鉴定及其对苯酚降解条件的优化

从降解苯酚的好氧颗粒污泥中筛选出一株苯酚降解菌,该菌株最高可耐受2.0 g/L的苯酚.依据形态特征和内源转录间隔区(ITS)的核酸序列分析,将该菌株鉴定为热带假丝酵母菌(Candida tropicalis),并命名为Candida tropicalis Z-04.采用中心复合设计(CCD)法对Candida trop...     

Biocatalytic amidation of carboxylic acids and their antinemic activity

A series of novel N-alkyl substituted amides, synthesized by enzyme catalysis, were evaluated against root-knot nematode, Meloidogyne incognita and found to have potential antinemic activity. The corresponding amides were prepared by the condensation of equimolar amounts of carboxylic acids with different alkyl amines in the presence of Candida antarctica lipase at 60–90°C in 16–20 h. The reactions were carried out in a non - solvent system without the use of any activating agents. All the products were obtained in appreciable amounts and the yields for different compounds varied between 77.4–82.3%. The synthesized compounds were characterized using spectroscopy techniques namely Infra Red (IR) and Nuclear Magnetic Resonance (NMR) (¹H and ¹³C). Nematicidal activity of synthesized amides was evaluated against J₂s of Meloidogyne incognita at 500, 250, 125 and 62.5 ppm concentrations after 24 h, 48 h and 72 h of exposure. Among all the tested compounds, N-propyl-butyramide, N-propyl-pentanamide and N-propyl-hexanamide were found to possess significant activity with LC₅₀ values of 67.46, 83.49 and 96.53 respectively. N-propyl-butyramide with LC₅₀ value of 67.46 ppm was found to be most active amide against J₂s of Meloidogyne incognita. The bioactivity study showed that an increase in alkyl chain significantly decreased the activity of amides against root-knot nematode.     

Candida utilis生物合成谷胱甘肽的营养及环境条件

研究了摇瓶条件下Candida utilis WSH02—08生物合成谷胱甘肽(GSH)的营养条件，确定以葡萄糖作为碳源，硫酸铵和尿素作为混合氮源．在L6(4^5)正交试验的基础上，选用BP神经网络对营养条件进行优化和预测，得出较优的营养组合为：葡萄糖30gL^-1(NH4)2SO4gL^-1，尿素4gL^-1，KH2PO4 3gL^-1，MgSO4 0．25gL^-1．研究了GSH发酵的环境条件，得出较优的组合为：初始pH6．0，装液量30mL／250mL，接种量10％．利用优化后的营养及环境条件进行摇瓶发酵实验，结果表明，GSH产量和细胞干重均有较大幅度的提高．图7表2参13     

麦芽糖假丝酵母10-4降解酚类化合物的研究

为了探索微生物处理多种酚类污染物的可能性,研究了高效脱酚菌麦芽假丝酵母１０－４对１５种酚类化合物的降解能力及降解生理。该菌能利用二元酚及三元酚为生长碳源,降解３种二元酚最快,３００ｍｇ／Ｌ浓度４８ｈ能去除９７％￣９９％,甲酚、硝基酚和氨基酚均不能作为生长碳源,硝基酚和氨基酚可以作为生长氮源。在培养基中添加碳,氮源可以明显促进该菌的生长和提高对这些取代酚的降解能力,３００ｍｇ／Ｌ浓度的单硝基酚可去除