Sequential batch reactor for eucalypt kraft pulp effluent treatment with Trametes versicolor

BACKGROUND: A sequential batch reactor (SBR) was used for eucalypt kraft pulp effluent treatment with Trametes versicolor. A 2³ full factorial design and response surface methodology were applied to optimise the batch fermentation conditions. Effluent concentration, culture medium and inoculum age were the factors selected for this study in order to optimise the reduction of chemical oxygen demand (COD). RESULTS: The presence of Trametes Defined Medium (TDM) in the fermentation was required to obtain a significant COD reduction. Experiments in the batch reactor confirmed, in general, the predicted results of optimisation developed from Erlenmeyer batch assays. The T. versicolor culture remained active during 42 days of study in the SBR, providing approximately 80% of COD reduction. CONCLUSION: Trametes versicolor may be considered as very promising for the biological treatment of effluents from kraft pulp mills in an SBR system instead of the activated sludge mixed cultures traditionally used. Copyright © 2008 Society of Chemical Industry     

Aerobic degradation by white‐rot fungi of trichloroethylene (TCE) and mixtures of TCE and perchloroethylene (PCE)

BACKGROUND: Trichloroethylene (TCE) and perchloroethylene (PCE) are considered among the most important groundwater pollutants around the world. These compounds are usually found together in polluted environments but little is known about the ability of microorganisms to simultaneously degrade TCE and PCE. RESULTS: Data showed that several species of white‐rot fungi, including Trametes versicolor, Ganoderma lucidum, and Irpex lacteus, degrade substantial levels of TCE in pure culture. T. versicolor was chosen for further study since it degraded higher levels of TCE than the other organisms. Initial glucose concentration and reoxygenation of samples increased the amount of TCE dechlorination, but no significant difference in percentage TCE degradation was observed. T. versicolor was able to degrade 34.1 and 47.7% of PCE and TCE added as mixtures (containing 5 and 10 mg L⁻¹, respectively). CONCLUSIONS: The degradation ability of TCE was extended to other species of white‐rot fungi. Percentage degradation as well as chloride release from mixtures of TCE and PCE showed that T. versicolor degrades mixtures of TCE and PCE almost as well as its ability to degrade individually added TCE or PCE. The results suggest the potential promise of T. versicolor for bioremediation of TCE and PCE in the environment. Copyright © 2008 Society of Chemical Industry     

杂色云芝漆酶的分离、纯化和酶学特性研究

杂色云芝发酵液,经超滤、DEAE-Sephadex A250柱层析两步分离、纯化出两型漆酶。以愈创木酚与酶带在适当条件下反应呈棕红色谱带鉴定出漆酶谱带。两型漆酶分别命名为LacA和LacB。经测定两漆酶亚基的分子量分别为66.0kDa和30.7kDa;等电点pI分别为4.79和5.18;LacA的最适作用温度是40℃,LacB为50℃;保温2h, LacA的半失活温度为60℃,LacB为90℃;LacA和LacB催化愈创木酚的酶活最适pH值均为4.0; 二者的稳定pH值也都在2.5~5.5之间。LacA催化氧化愈创木酚的Km和Vmax分别为286.5molL-1和292.4nmol mL-1 min-1;LacB催化氧化愈创木酚的Km和Vmax分别为813.0mol L-1和127.4nmol mL-1 min-1。     

Polystictus versicolor对糖厂离子交换再生液脱色及产多糖研究

利用Polystietus versieolor研究对糖厂离子交换再生液脱色及产生多糖的影响。在测定离子交换再生液成份的基础上，两倍稀释培养用离子交换再生液。研究了5L生物反应器放大过程中培养液pH值、还原糖与脱色率、化学好氧量、菌体生物量、多糖产量，以及透射电镜观察菌体细胞壁的变化，结果表明将原始废水两倍稀释，调整还原糖浓度到1％。添加适量的生物素，用通气搅拌发酵罐进行放太试验，可以缩短培养时间。培养52h，脱色串即可达到83％，COD的去除率达到72％，表现出强的有机负荷承受能力。菌丝体多糖产率提高，细胞壁增厚，证明废水中的大分子色素物质有利于转化为云芝菌丝体胞壁多糖。     

云芝多糖研究进展

近年来,药食用真菌因具有多种生物学功能而受到重视,成为研究热点。云芝多糖由云芝或从其发酵液中分离提取,具有突出的药食用功效和生物活性。文中从云芝多糖的结构、性质、提取纯化、发酵生产、用途与展望等方面进行了综述,为云芝多糖的进一步研究与开发提供参考。     

铜在含氯薄液膜和杂色曲霉作用下的腐蚀行为

目的 研究纯铜在含氯液膜和霉菌共同作用下的腐蚀行为与机理。方法 将海南文昌采集的一株野生杂色曲霉接种到质量分数分别为0.9%和3.5%的NaCl溶液中制成孢子悬浮液,将孢子悬浮液均匀喷洒到铜试样表面后进行恒温恒湿试验,试验不同周期后采用体视学显微镜、扫描电子显微镜观察铜试样的腐蚀形貌,采用X射线光电子能谱仪分析试验14 d的试样表面和氩离子刻蚀15 s后的成分。结果 纯铜在NaCl薄液膜下的腐蚀产物具有明显的双层结构,内层靠近基体的为致密的Cu2O钝化层,外层为疏松的Cu2(OH)2CO3和Cu2(OH)3Cl组成的Cu(II)碱式盐;无菌时,铜表面出现大量蓝绿色的Cu(II)碱式盐,杂色曲霉存在时,铜表面腐蚀产物主要为红棕色的Cu2O钝化膜,仅有少量Cu(II)碱式盐零星分布在Cu2O膜外层;0.9% NaCl薄液膜与霉菌共同作用时,试样表面腐蚀产物主要为Cu2O,当薄液膜中盐的质量分数升高到3.5%时,霉菌数量减少,Cu(II)碱式盐较0.9% NaCl薄液膜组增多。结论 纯铜的腐蚀产物由内层的Cu2O钝化层、外层的Cu2(OH)2CO3和Cu2(OH)3Cl组成双层结构。杂色曲霉通过呼吸作用影响液膜中的O2浓度进而影响铜的腐蚀产物组成,霉菌存在时腐蚀产物中Cu(II)碱式盐显著减少。含氯液膜与霉菌共同作用时,液膜中的NaCl浓度通过影响杂色曲霉的生长活性而影响腐蚀产物组成。     

Decrease of the chlorogenic acid content in commercial sunflower meal using a polyphenol oxidase preparation secreted by the white‐rot fungus Trametes versicolor ATCC 42530

BACKGROUND: Sunflower meal (SFM) is a by‐product from the oil extraction process from sunflower seeds. The meal is used as a protein supplement in the livestock diet. However, relatively high levels of polyphenols, among which chlorogenic (CGA) and caffeic acids are in larger amounts, in the meal compromises its use for animal feed and human consumption. The aim of this work was to investigate an enzymatic process for upgrading the quality of SFM by decreasing its CGA content using an enzyme preparation from the white‐rot fungus Trametes versicolor. RESULTS: The effects of pH, temperature, enzyme and meal concentrations, and mass transfer on the decrease of the CGA content in SFM were investigated. It was found that: (1) the optimum pH and temperature were 3.4 and 45 °C, respectively. (2) The system was saturated with the enzyme when its concentration was 5 nkat/mL of liquid phase; (3) the agitation speed of the system influenced the extraction of CGA from the meal; and (4) the conversion of CGA in the SFM system increased in the presence of larger volumes of liquid phase. CONCLUSIONS: The enzyme preparation used in the experiments is able to decrease successfully the CGA content in SFM. Copyright © 2007 Society of Chemical Industry     

Herbal infusions bioelectrochemical polyphenolic index: Green tea – The gallic acid interference

An amperometric biosensor containing immobilised laccase from Trametes versicolor was used for the quantification of phenolic compounds in herbal infusions and green tea samples, from nine botanical families. The main purpose of this research was to correlate the bioelectrochemical polyphenolic index (BPI) of the samples with the total phenolic content according to the Folin–Ciocalteu spectrophotometric method (TPC), and the total antioxidant activity (TAA) measured by TEAC (Trolox Equivalent Antioxidant Capacity). A strong correlation between BPI, TPC, and TAA was obtained for 10 herbal infusion samples. However, when a green tea sample was taken into account, a decrease in the linear correlation coefficient (r²) from 0.9949 to 0.2599 and 0.5609 to 0.1086 for the relationship between BPI/TPC and BPI/TAA, respectively, was observed. Thus, we could conclude that the green tea’s matrix affects the laccase-based biosensor response. HPLC–DAD analysis showed the presence of gallic acid only in the green tea sample. The results have indicated that gallic acid inhibited the laccase activity regarding the ABTS oxidation in a concentration-dependent manner. The very strong correlation between BPI/TPC obtained for herbal infusions allow us to conclude that the laccase-based biosensor, used in this research, provides a valuable tool to obtain a valid estimation of the classical Folin–Ciocalteu index, in an uncomplicated and fast way.     

Biodegradation of sulfamethazine by Trametes versicolor: Removal from sewage sludge and identification of intermediate products by UPLC-QqTOF-MS

Degradation of the sulfonamide sulfamethazine (SMZ) by the white-rot fungus Trametes versicolor was assessed. Elimination was achieved to nearly undetectable levels after 20 h in liquid medium when SMZ was added at 9 mg L^− 1. Experiments with purified laccase and laccase-mediators resulted in almost complete removal. On the other hand, inhibition of SMZ degradation was observed when piperonilbutoxide, a cytochrome P450-inhibitor, was added to the fungal cultures. UPLC-QqTOF-MS analysis allowed the identification and confirmation of 4 different SMZ degradation intermediates produced by fungal cultures or purified laccase: desulfo-SMZ, N⁴-formyl-SMZ, N⁴-hydroxy-SMZ and desamino-SMZ; nonetheless SMZ mineralization was not demonstrated with the isotopically labeled sulfamethazine-phenyl-¹³C₆ after 7 days. Inoculation of T. versicolor to sterilized sewage sludge in solid-phase systems showed complete elimination of SMZ and also of other sulfonamides (sulfapyridine, sulfathiazole) at real environmental concentrations, making this fungus an interesting candidate for further remediation research.     

白腐菌Trametes sp. Lg-9粗酶液预处理对杨木SCMP性能的影响

研究了白腐菌Trametes sp. Lg-9粗酶液预处理对磺化化学机械浆（SCMP）性能的影响。结果表明：Lg-9粗酶液预处理可改善SCMP的打浆性能,降低打浆能量消耗,预处理后打浆的纤维平均长度增大,细小组分含量降低,宽度稍有增大。Trametes sp. Lg-9粗酶液预处理可提高SCMP白度,改善强度。Trametes sp. Lg-9粗酶液预处理的漂后浆纤维平均长度较长,细小组分含量较少,粗酶液用量大于8IU/g浆时,随着粗酶液用量的增大,纤维平均长度有所降低,细小组分含量有所提高。