一种pH相对稳定的栓菌T. sp. SQ01漆酶

漆酶 (p-diplaenol:oxygen oxidorecluctase,EC 1.10.3.2)在生物制浆、生物漂白、脱色以及有毒化合物的降解等方面具有较为广泛的应用前景,同时也是相关学科领域的研究热点.     

粗毛栓菌诱变菌株SAH-12漆酶的分离纯化及酶学性质研究

粗毛栓菌Trametes gallica诱变菌株SAH-12是通过紫外诱变选育所得的漆酶高产菌株,Active-PAGE分析表明SAH-12在高氮低碳无机盐培养液（LM3）中至少分泌3种漆酶同工酶（Lac1、Lac2、Lac3）。采用硫酸铵盐析、透析和Sephadex-G75分子筛层析从其培养液中分离纯化得到电泳纯的Lac1,纯化倍数6.54,酶活性回收59.7%。Lac1经SDS-PAGE验证为一条带,其表观分子量为61.5kDa。Lac1为一种糖蛋白,含糖量11.6%,等电点pI4.40,催化氧化底物ABTS的最适反应温度为60℃,最适pH为2.6,Km值为25μmol/L。Lac1在40℃（pH4.0）以下和pH1.5～5.0（28℃）范围内稳定。金属离子Fe2＋、Ag＋、Hg2＋和Cr3＋与抑制剂DTT、SDS、EDTA和DMSO对Lac1有抑制作用,其中Fe2＋和DTT完全抑制酶活,而Cu2＋对酶有明显激活作用,Mn2＋、Zn2＋对酶活影响不大。Lac1不仅可使一些合成染料明显脱色,而且对苹果汁多酚祛除也有较好效果。40℃用该酶（1U/mL）处理苹果汁5h,其多酚含量可降低40%。     

Decolorization of reactive dyes by a thermostable laccase produced by Ganoderma lucidum in solid state culture

Dye decolorizing potential of the white rot fungus Ganoderma lucidum KMK2 was demonstrated for recalcitrant textile dyes. G. lucidum produced laccase as the dominant lignolytic enzyme during solid state fermentation (SSF) of wheat bran (WB), a natural lignocellulosic substrate. Crude enzyme shows excellent decolorization activity to anthraquinone dye Remazol Brilliant Blue R (RBBR) without redox mediator whereas diazo dye Remazol Black-5 (RB-5) requires a redox mediator. Polyacrylamide gel electrophoresis (PAGE) of crude enzyme confirms that the laccase enzyme was the major enzyme involved in decolorization of either dyes. Native and SDS-PAGE indicates that the presence of single laccase with molecular weight of 43 kDa. N-Hydroxybenzotriazole (HBT) at a concentration of 1 mM was found as the best redox mediator. RB-5 (50 mg l^−l) was decolorized by 62% and 77.4% within 1 and 2 h, respectively by the crude laccase (25 U ml⁻¹). RBBR (50 mg l^−l) was decolorized by 90% within 20 h, however, it was more efficient in presence of HBT showing 92% decolorization within 2 h. Crude laccase showed high thermostability and maximum decolorization activity at 60 °C and pH 4.0. The decolorization was completely inhibited by the laccase inhibitor sodium azide (0.5 mM). Enzyme inactivation method is a good method which averts the undesirable color formation in the reaction mixture after decolorization. High thermostability and efficient decolorization suggest that this crude enzyme could be effectively used to decolorize the synthetic dyes from effluents.     

粗毛栓菌诱变菌株SAH-12漆酶的分离纯化及酶学性质研究

粗毛栓菌Trametes gallica诱变菌株SAH-12是通过紫外诱变选育所得的漆酶高产菌株,Active-PAGE分析表明SAH-12在高氮低碳无机盐培养液(LM3)中至少分泌3种漆酶同工酶(Lac1、Lac2、Lac3)。采用硫酸铵盐析、透析和Sephadex-G75分子筛层析从其培养液中分离纯化得到电泳纯的Lac1,纯化倍数6.54,酶活性回收59.7%。Lac1经SDS-PAGE验证为一条带,其表观分子量为61.5kDa。Lac1为一种糖蛋白,含糖量11.6%,等电点pI4.40,催化氧化底物ABTS的最适反应温度为60℃,最适pH为2.6,Km值为25μmol/L。Lac1在40℃(pH4.0)以下和pH1.5～5.0(28℃)范围内稳定。金属离子Fe2+、Ag+、Hg2+和Cr3+与抑制剂DTT、SDS、EDTA和DMSO对Lac1有抑制作用,其中Fe2+和DTT完全抑制酶活,而Cu2+对酶有明显激活作用,Mn2+、Zn2+对酶活影响不大。Lac1不仅可使一些合成染料明显脱色,而且对苹果汁多酚祛除也有较好效果。40℃用该酶(1U/mL)处理苹果汁5h,其多酚含量可降低40%。     

猴头菌多糖脱色前后理化性质及生物活性的研究

以脱色前、后的猴头菌Hericium erinaceus粗多糖为研究对象,对其多糖含量、多糖中的单糖组成、分子量分布、红外光谱等理化性质和体外免疫活性、胃粘膜损伤的修复作用进行了比较研究。结果表明,猴头菌多糖脱色后,多糖含量提高、蛋白含量下降、小分子物质大量减少、单糖种类基本不变,岩藻糖所占比例略有下降、半乳糖及葡萄糖比例略有上升,红外光谱显示,脱色后多糖中的C=O基团减少;多糖脱色后体外免疫活性显著提高（P<0.05）,低浓度的未脱色多糖与模型组相比,对胃粘膜的损伤修复作用无显著性差异（P<0.05）,而低浓度的脱色多糖对胃粘膜的损伤修复作用显著提高（P<0.01）。     

Identification and Growth Characteristics of α-Galactosidase-producing Microorganisms

Two kinds of α-galactosidase-producing microorganisms, strain No. 31–2 and strain No. 7–5, have been isolated from soil and subjected to a determinative study. On the basis of the morphological and physiological characters, the strain No. 31–2 was identified to be belonged to genus Micrococcus and the strain No. 7–5 to genus Bacillus. The former strain, Micrococcus sp. No. 31–2, produced exclusively an intracellular α-galactosidase, and the latter one, Bacillus sp. No. 7–5, secreted the enzyme into culture medium. The cell growth and enzyme production of both strains were observed to reach the maximum under an alkaline culture condition. The intracellular α-galactosidase of Micrococcus sp. No. 31–2 was inducible by galactose, melibiose, and raffinose, while the α-galactosidase of Bacillus sp. No. 7–5 was produced constitutively.     

Structural Alteration of Humic Acids by Pseudomonas spp. from Deep Terrestrial Subsurface Diatomite Formations in Northernmost Japan

Bacterial utilization of humic acids (HAs) was examined under aerobic conditions using Pseudomonas spp. from diatomite from a depth of 250 m below ground level in the Horonobe Underground Research Laboratory. HA decolorization and bacterial aggregation were observed during cultivation when an auxiliary carbon source was added. High-performance size-exclusion chromatography showed that high-molecular-weight HAs were produced. Fourier transform infrared spectroscopy indicated that carboxyl groups and polysaccharide-related substances in HAs were eliminated, while aliphatic structural units and amide groups were added to HAs. These results suggested that Pseudomonas spp. utilize and alter the molecular structure of HAs under aerobic conditions caused by the construction of underground facilities.     

Enhanced decolorization of sulfonated azo dye methyl orange by single and mixed bacterial strains AK1, AK2 and VKY1

Abstract

Methyl orange, a sulfonated azo dye having various industrial applications was decolorized by three bacteria Bacillus sp. strain AK1, Lysinibacillus sp. strain AK2 and Kerstersia sp. strain VKY1. The effect of various factors such as dye concentration, pH, temperature and NaCl concentration on decolorization was investigated. At 200?mg/L methyl orange concentration, the strains AK1, AK2 and VKY1 exhibited maximum decolorizing potential of 93, 95 and 96%, respectively, at temperature 35?°C and pH 7.0 within 18?h of incubation. These strains decolorized the dye over a wide range of pH (5–10), temperature (15–55?°C), and NaCl concentration (5–20?g/L). Further, these strains decolorize up to 800?mg/L concentrations of methyl orange within 24?h. The dye decolorization efficiency was further increased by using different consortia of these three strains which could decolorize the dye completely within 12?h of incubation. The cell-free extracts of the strains AK1, AK2 and VKY1 grown on methyl orange exhibited the azoreductase activity of 0.4794, 1.56 and 1.01?µM/min/mg protein, respectively. HPLC and FTIR analysis of the dye decolorized sample indicated the formation of 4-aminobenzenesulfonic acid and N,N-dimethyl-p-phenylenediamine as breakdown products of azo bond. The high decolorization potential of these bacterial strains individually and in consortia has potential application in remediation of dye effluent.     

Biosorption of Basic Blue 7 by fungal cells immobilized on the green-type biomatrix of Phragmites australis spongy tissue

Biosorption is an effective alternative method for the control of water pollution caused by different pollutants such as synthetic dyes and metals. A new and efficient biomass system was developed from the passively immobilized fungal cells. The spongy tissue of Phragmites australis was considered as the carrier for the immobilization of Neurospora sitophila cells employed for the biosorption of Basic Blue 7. This plant tissue was used for the first time as a carrier for fungal cells. The biosorption was examined through batch- and continuous-mode operations. The biosorption process conformed well to the Langmuir model. Maximum monolayer biosorption capacity of the biosorbent was recorded as 154.756 mg g^?1. Kinetic findings showed a very good compliance with the pseudo-second-order model. The negative values of ΔG° indicated a spontaneous nature of the biosorption process and a positive value of ΔH° (14.69 kJ mol^?1) concluded favorable decolorization at high temperature. The scanning electron microscopy analysis showed that a porous, rippled, and rough surface of biomass system was covered with BB7 molecular cloud. IR results revealed that functional groups like –OH, –NH, and C?O participated to the decolorization. Breakthrough and exhausted points were found as 360 and 570 minutes, respectively. The biomass system was successfully applied to the treatment of real wastewater.