Degradation of isoproturon by the white rot fungus Phanerochaete chrysosporium

The ability of the white rot fungus Phanerochaete chrysosporium to degrade isoproturon was tested in solid substrate fermentation (SSF) cultures using straw as substrate/carrier material. The role of the lignin degrading enzymes, lignin peroxidase (LiP) and manganese peroxidase (MnP), in the degradation of the herbicide was also studied. Isoproturon concentration and LiP and MnP activities were followed in sterile straw cultures of the fungus. In vitro degradation tests with pure LiP and MnP were performed. P. chrysosporium in straw cultures was able to degrade 91% of the herbicide isoproturon in 14 days of incubation. A sharp decrease of isoproturon coincided with the largest MnP activity. Although LiP activity was also present, its role in SSF is unclear. The in vitro tests showed a strong isoproturon oxidation by LiP and a slower oxidation by MnP in the presence of Tween 80 probably by a lipid peroxidation process. Two N-demethylated metabolites were identified in pure enzyme tests and in SSF cultures. Several unidentified isoproturon derivatives, most likely hydroxylated, were also formed in both systems. The different pattern of derivatives detected in pure LiP and MnP tests showed a completely different metabolism by these two enzymes.     

Kinetics and Energetics of Azo Dye Decolorization by Pycnoporus sanguineus

Trypan Blue, an azo dye, was decolorized using the self-immobilizing fungal biomass of Pycnoporus sanguineus. The extent and the rate of dye decolorization were directly proportional to the initial dye concentration (20–60 mg L^?1) and the reaction temperature (25–45°C). Mass transfer within and outside the pellets did not limit dye degradation. The apparent kinetics of the decolorization reaction followed a first-order behavior. Activation energy for the biological decolorization was calculated at 23 kJ mol^?1. The decolorization process was endothermic with the enthalpy and entropy values calculated at 45.6 kJ mol^?1 and 146 J mol^?1 K^?1, respectively. Based on the value of Gibbs free energy change, the decolorization reaction under the conditions studied was non-spontaneous below 39°C but was spontaneous at higher temperatures.     

黑曲霉和米曲霉发酵改善豆渣口感

豆渣作为豆制品生产的副产品,富含营养。为了解决豆渣颗粒大,口感差,难以直接食用的问题,该文对利用黑曲霉和米曲霉发酵豆渣降低其粒度分布进而改善其口感、增加其可食性进行了研究。结果表明:利用黑曲霉和米曲霉在28℃,相对湿度为95%的条件下发酵,能使渣感减弱,吞咽变易,口感明显改善;对发酵10d后豆渣的外观形态、显微镜观察、粒度分布进行考察,均一致表现为发酵后豆渣颗粒显著变小;黑曲霉发酵豆渣对渣感的降低效果好于米曲霉发酵豆渣和未发酵豆渣;发酵使豆渣颗粒变小是口感改善的主要原因;口感改善的根本原因是发酵豆渣过程中所产生的纤维素酶和半纤维素酶降解了豆渣中的纤维素和半纤维素,导致豆渣颗粒变小的缘故。该研究对豆渣的综合利用提供了新途径。     

Detoxification of corn stover and corn starch pyrolysis liquors by ligninolytic enzymes of Phanerochaete chrysosporium

Phanerochaete chrysosporium (ATCC 24725) shake flask culture with 3 mM veratryl alcohol addition on day 3 was able to grow and detoxify different concentrations of diluted corn stover (Dcs) and diluted corn starch (Dst) pyrolysis liquors [10, 25, and 50% (v/v)] in defined media. GC-MS analysis of reaction products showed a decrease and change in some compounds. In addition, the total phenolic assay with Dcs samples demonstrated a decrease in the phenolic compounds. A bioassay employing Lactobacillus casei growth and lactic acid production was developed to confirm the removal of toxic compounds from 10 and 25% (v/v) Dcs and Dst by the lignolytic enzymes, but not from 50% (v/v) Dcs and Dst. The removal did not occur when sodium azide or cycloheximide was added to Ph. chrysosporium culture media, confirming the participation of lignolytic enzymes in the detoxification process. A concentrated enzyme preparation decreased the phenolic compounds in 10% (v/v) corn stover and corn starch pyrolysis liquors to the same extent as the fungal cultures.     

Photocatalytic Degradation of Azo Dye Reactive Orange 16 by TiO2

Water, Air, & Soil Pollution - Several recent reports document increasing concentrations of chloride in surface waters of northeastern and midwestern North America. These patterns, together...     

Solid-substrate fermentation of corn fiber by Phanerochaete chrysosporium and subsequent fermentation of hydrolysate into ethanol

The goal of this study was to develop a fungal process for ethanol production from corn fiber. Laboratory-scale solid-substrate fermentation was performed using the white-rot fungus Phanerochaete chrysosporium in 1 L polypropylene bottles as reactors via incubation at 37 degrees C for up to 3 days. Extracellular enzymes produced in situ by P. chrysosporium degraded lignin and enhanced saccharification of polysaccharides in corn fiber. The percentage biomass weight loss and Klason lignin reduction were 34 and 41%, respectively. Anaerobic incubation at 37 degrees C following 2 day incubation reduced the fungal sugar consumption and enhanced the in situ cellulolytic enzyme activities. Two days of aerobic solid-substrate fermentation of corn fiber with P. chrysosporium, followed by anaerobic static submerged-culture fermentation resulted in 1.7 g of ethanol/100 g of corn fiber in 6 days, whereas yeast ( Saccharomyces cerevisiae) cocultured with P. chrysosporium demonstrated enhanced ethanol production of 3 g of ethanol/100 g of corn fiber. Specific enzyme activity assays suggested starch and hemi/cellulose contribution of fermentable sugar.     

Ligninolytic enzyme production by Phanerochaete chrysosporium in plastic composite support biofilm stirred tank bioreactors

Phanerochaete chrysosporium (ATCC 24725) produced lignin peroxidase (LiP) and manganese peroxidase (MnP) in defined medium in plastic composite support (PCS) biofilm stirred tank reactors. Laccase was not detected. The formation of the Ph. chrysosporium biofilm on the PCS was essential for the production of MnP and LiP. The bioreactor was operated as a repeat batch, and no reinoculation was required between batches. Peroxidase production was influenced by 5 min purging of the bioreactor with pure oxygen or continuous aerating with a mixture of air and oxygen at a flow rate of 0.005 vvm. Continuous aeration and 300 rpm agitation with 3 mM veratryl alcohol addition on days 0 and 3 demonstrated the highest lignin peroxidase production on day 6 with means of 50.0 and 47.0 U/L. Addition of veratryl alcohol and MnSO(4) on day 0 with 300 rpm agitation and continuous aeration at 0.005 vvm (air flow rate in L/min divided by the reactor working volume in liters) hastens the production of MnP with final yield of 63.0 U/L after 3 days. Fourteen repeated batches fermentation were performed without contamination due to low pH (4.5) and aseptic techniques employed.     

Comparative Study on Photocatalytic Degradation of Mono Azo Dye Acid Orange 7 and Methyl Orange under Solar Light Irradiation

The objective of this study was to investigate and compare the kinetic photocatalytic degradation of mono azo dyes Acid Orange 7 (AO7) and Methyl Orange (MO) under solar light irradiation with titanium dioxide (TiO₂) as a photocatalyst. Several operational parameters affecting the photocatalytic degradation of dye were evaluated such as different azo dyes, initial dye concentration, TiO₂ dosage, with and without aeration and sunlight irradiation. The data obtained was well fitted with the Langmuir?CHinshelwood kinetic model. It was observed that the pseudo-first-order rate constants for AO7 were higher than MO in all cases, indicating that the photocatalytic degradation of AO7 was easier and more rapid than MO. The analysis of chemical oxygen demand and UV?CVis spectra shows the AO7 and MO not only being decolorized due to the breakdown of azo bond but also being mineralized if the azo dye solutions were continually exposed to solar light irradiation after the decolorization process.     

Biotreatment of Melanoidin-Containing Distillery Spent Wash Effluent by Free and Immobilized Aspergillus oryzae MTCC 7691

Humic acids (HA) are known as the precursors of carcinogenic compounds formed by the disinfection of drinking water. While conventional treatments were found to be inefficient HA removal processes in drinking water, advanced oxidation processes have been proven to have a significant effect in the treatment of HA. The degradation of HA was investigated using nano-sized zinc oxide (ZnO)/laponite composite (NZLC). The reactions occurred in a UVC reactor by considering following variables: pH, initial HA concentration, catalyst loading, addition of hydrogen peroxide (H₂O₂), and catalyst reuse. Water samples containing HA were analysed by ultraviolet/visible spectrophotometer and high-performance size-exclusion chromatography. Initial HA concentrations were tested by the Langmuir–Hinshelwood model with k and K _ads values, determined to be 0.126 mg/L.min and 0.0257 L/mg, respectively. The change in pH affected the HA degradation efficiency by the photocatalytic activity where it was higher under acidic conditions rather than alkaline ones. Optimal catalyst loading was proved to be a constrained factor in influencing the photocatalytic efficiency: the increase of catalyst concentration enhanced the HA decomposition efficiency up to an optimum value of 20 g/L, where there was no further degradation with excess loading. The addition of H₂O₂ was investigated through homogenous and heterogeneous photocatalysis, and, heterogeneous photocatalysis showed higher removal efficiency due to the combined effect of both catalysts and H₂O₂. Finally, NZLC was effective for reuse and exhibited an excellent stability after six times of usage.     

Isolation and characterization of an extracellular antimicrobial protein from Aspergillus oryzae

A 17 kDa antimicrobial protein was isolated from growth medium containing the filamentous fungus Aspergillus oryzae by extracting the supernatants from the culture media, ion exchange chromatography on CM-sepharose, and C18 reverse-phase high-performance liquid chromatography. This antimicrobial protein, which we considered to be an extracellular antimicrobial protein from A. oryzae (exAP-AO17), possessed antimicrobial activity but lacked hemolytic activity. The exAP-AO17 protein strongly inhibited pathogenic microbial strains, including pathogenic fungi, Fusarium moniliform var. subglutinans and Colletotrichum coccodes, and showed antibacterial activity against bacteria, including E. coli O157 and Staphylococcus aureus. To confirm that the protein acts as a regulation factor for extracellular secretion, we examined growth under varying conditions of N sources, C sources, ions, ambient pH, and stress. Various culture conditions were found to induce characteristic changes in the expression of protein synthesis as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Highly basic polypeptides were regulated by suppressing the ambient pH under acidic conditions and strongly induced under alkaline conditions, thus confirming that pH regulation is physiologically relevant. The expression of exAP-AO17 was upregulated by heat shock upon growth in the presence of NaCl. Automated Edman degradation showed that the N-terminal sequence of exAP-AO17 was NH 2-GLPGPAGAVGFAGKDQNM-. ExAP-AO17 showed partial sequence homology with a collagen belonging to the animal source. These results suggest that exAP-AO17 is an excellent candidate as a lead compound for the development of novel oral or other types of anti-infective agents.     

Purification and properties of a novel phenolic antioxidant from Radix astragali fermented by Aspergillus oryzae M29

The Chinese herb Radix astragalus (RA) has been widely used as a dietary supplement in Asia, and there are numerous reports on its bioactivities. However, there are no reports to date regarding the use of Aspergillus spp. in the culture medium of the RA plant for the production of phenolic antioxidants. In this study, utilizing the fungus Aspergillus to ferment the native RA has successfully resulted in a significant increase in the phenolic contents of RA, and the fermented RA also revealed much better antioxidant activity toward 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals, hydroxyl radical, superoxide radical and peroxyl radical than those of unfermented RA. Among these phenolics, a potent novel antioxidant was isolated and identified as 3,4-di(4'-hydroxyphenyl) isobutyric acid with a molecular weight of 272, by ESI-MS (electrospray ionization mass), 1H NMR (nuclear magnetic resonance), 13C NMR, DEPT (distortionless enhancement by polarization transfer)-NMR, HMQC (heteronuclear multiple quantum coherence), and HMBC (heteronuclear multiple bond correlation) spectra. These data demonstrated that the solid-state bioprocessing strategy could be an innovative approach to enhance the antioxidant activity of RA.     

Thermal stability of alpha-amylase from Aspergillus oryzae entrapped in polyacrylamide gel

To determine the suitability as a time-temperature indicator for dielectric pasteurization processes, the thermal stability (50-75 degrees C) of Aspergillus oryzae alpha-amylase immobilized in polyacrylamide gel in phosphate buffer, mashed potatoes, and minced shrimp was examined. Changing the cross-linking agent concentration from 3.3 to 5.3% and adding 2% salt did not markedly affect the thermal stability of the immobilized alpha-amylase. Thermal inactivation was first order, and immobilization generally improved the thermal stability of alpha-amylase. z values of the immobilized system in test food systems were 10.2 degrees C (phosphate buffer), 8.45 degrees C (minced shrimp), and 7.78 degrees C (mashed potatoes).     

Synthesis of morphiceptin (Tyr-Pro-Phe-Pro-NH(2)) by dipeptidyl aminopeptidase IV derived from Aspergillus oryzae

Morphiceptin (Tyr-Pro-Phe-Pro-NH(2)), tetrapeptide, was synthesized using dipeptidyl aminopeptidase IV (DP IV, EC 3.4.14.5) derived from Aspergillus oryzae RIB 915 as a catalyst. Tyr-Pro-OEt was incubated with Phe-Pro-NH(2) in the presence of DP IV under various conditions of temperature, concentrations of ethylene glycol, pH, reaction time, and others. Morphiceptin was obtained at 40% yield under the optimal reaction conditions: substrate, 4 mM Tyr-Pro-OEt.HCl and 20 mM Phe-Pro-NH(2).HCl; enzyme, DP IV, 0.275 nkat; solvent, 60% ethylene glycol containing 20 mM phosphate buffer at pH 7.0; amine, 4.2 mM diisopropylamine at 4 degrees C for 24 h. Amino group protection was unnecessary for synthesis of morphiceptin by DP IV.     

Nutritional Enhancement of Soy Meal via Aspergillus oryzae Solid‐State Fermentation

Antinutritional factors in soy meal (SM) include trypsin inhibitor, galactooligosaccharides (GOSs), structural polysaccharides, and large‐molecular‐weight protein. These antinutritional factors limit the usage of SM for young monogastric animals. Aspergillus oryzae solid‐state fermentation was applied to eliminate these factors, and changes in physical and chemical characteristics of SM were investigated. A. oryzae–treated SM was more nutrient dependent than oxygen dependent, which was illustrated by scanning electron microscopy. After 36 h of fermentation, the concentration of GOSs (raffinose, stachyose, and verbascose) and trypsin inhibitor decreased from an initial value of 9.48 mmol/100 g to a nondetectable level. Structural polysaccharides decreased by 59% (w/w), and the degree of hydrolysis of SM protein increased from an initial value of 0.9 to 7% (w/w) through the seven‐day fermentation. Fermentation also modified nutritional factors. Protein content increased from 50.47 to 58.93% (w/w) after 36 h of fermentation. Amino acid contents were significantly enhanced. The research thoroughly studied the A. oryzae solid‐state fermentation of SM, and the resulting premium product could provide a better protein source for monogastric animals.     

水稻白叶枯病黄单胞菌赖氨酰－tRNA合成酶基因的定位、克隆及分析

以３２Ｐ标记的甘蓝黑腐病黄单胞菌赖氨酰－ｔＲＮＡ合成酶基因为探针，将水稻白叶枯病黄单胞菌同功的基因定位于ｐＧＸＮ３０００１．６ｋｂ的ＢａｍＨＩ片段上．通过ＤＮＡ－ＤＮＡ杂交，标记置换等方法初步证实：在稻白叶枯病黄单胞菌中只有一个拷贝的赖氨酰－ｔＲＮＡ合成酶基因，该基因失活对病菌是致死的。     

Biodegradation of beta-cyfluthrin by fungi

Five fungal species, namely, Trichoderma viride strain 5-2, T. viride strain 2211, Aspergillus niger, A. terricola, and Phanerochaete chrysoporium were screened for degradation study of beta-cyfluthrin. Each fungal species was allowed to grow in Czapek dox medium containing beta-cyfluthrin (5 mg/mL) as the major carbon source of the medium. The highest degradation of beta-cyfluthrin was observed by T. viride 5-2 (T(1/2) = 7.07 days), followed by T.viride 2211 (T(1/2) = 10.66 days). The degradation of beta-cyfluthrin followed first-order kinetics with a fast degradation rate during first 7 days of growth of the fungi. In the case of T. viride strain 5-2, five degradation products were isolated after 20 days of growth of the fungi, out of which three products were identified as alpha-cyano-4-fluorobenzyl-3- (2,2-dichlorovinyl)-2,2-dimethyl cyclopropane carboxylate, alpha-cyano-4-fluoro-3-phenoxy benzyl alcohol, and 3(2,2-dichlorovinyl)-2,2-dimethyl cyclopropanoic acid.     

Corncob-induced endo-1,4-beta-d-xylanase of Aspergillus oryzae MTCC 5154: production and characterization of xylobiose from glucuronoxylan

Eight different fungi were cultivated in a peptone-yeast extract medium containing 1% oat spelt xylan (OSX) to evaluate endo-1,4-beta-xylanase secretion for xylooligosaccharide (XOS) production. Aspergillus oryzae MTCC 5154, Aspergillus flavus , Aspergillus niger , and Aspergillus ochraceus showed significant titers of endoxylanases, which were further used for the production of XOS from birch wood xylan (BWX). A. oryzae produced 89.5 +/- 1.13% XOS in the hydrolysate at 24 h of reaction. The effect of OSX, BWX, and raw corncob on the induction of endoxylanase in A. oryzae was studied, and the xylanase activity was maximum at 96 h of cultivation in 3% corncob containing medium. XOS produced at 36 h of reaction was 5.87 +/- 0.53 mg/mL (12 +/- 2% xylose, 48 +/- 2.43% xylobiose, and 40 +/- 3.6% higher oligomers) from 1% BWX . HPLC/refractive index detection and ESI/MS analysis of fractions obtained by GPC corresponded to neutral and 4- O-methyl-alpha- d-glucuronic acid substituted acidic oligosaccharides. The major fraction, beta- d-xylopyranosyl-(1-->4)- d-xylanopyranose was characterized using (13)C NMR.     

水稻受白叶枯病菌诱导抗性相关基因片段的克隆

利用已知植物Ｒ类基因保守结构域,设计简并引物作为随机引物,运用ｍＲＮＡ差异显示技术,分析水稻愈伤组织受白叶枯病菌诱导的ｍＲＮＡ表达丰度差异,获得３个差异片段。对３个差异片段进行了回收、重扩增与克隆,并对其中的一个差异片段进行了序列测定和杂交鉴定。该片段长度为６８０ ｂｐ,Ｎｏｒｔｈｅｒｎ杂交结果证实该片段受白叶枯病菌诱导表达且在抗性品种中的诱导表达明显强于在感病品种中的诱导表达。Ｓｏｕｔｈｅｒｎ杂