Role of veratryl alcohol in lignin degradation by Phanerochaete chrysosporium

Several aromatic compounds increased initial lignin degradation rates in cultures of Phanerochaete chrysosporium. This activation was connected to increased H₂O₂ production and glucose oxidation rates. Veratryl alcohol, a natural secondary metabolite of P. chrysosporium, also activated the lignin-degrading system. In the presence of added veratryl alcohol the ligninolytic system appeared 6–8 h earlier than in reference cultures. This effect was only seen when lignin was added after the primary growth was completed because lignin itself also caused earlier appearance of the degradative system. In cultures which received no added lignin or veratryl alcohol the ligninolytic activity only appeared once the alcohol started to accumulate. The degradation patterns of veratryl alcohol and lignin were similar. The activity levels of lignin degradation and glucose oxidation could be regulated by veratryl alcohol concentration. It is suggested that either veratryl alcohol itself or a metabolite derived from it is actually responsible for the low levels of ligninolytic activity in glucose grown cultures.     

Effects of organic acid fractions extracted from Eucalyptus camaldulensis leaves on root elongation of maize (Zea mays) in the presence and absence of aluminium

Complexes of aluminium (Al) with organic ligands are believed to represent an important detoxification mechanism in acid soils. However, relatively little is known about the particular ligands produced by decomposing vegetation or about their effects on plant growth in the presence or absence of toxic Al. This paper reports an experiment on the effects of decomposition products of Eucalyptus camaldulensis leaves on the root elongation of maize (Zea mays) cv. DK687 in the presence or absence of Al. The static solution culture experiment used fulvic acid (FA) and humic acid (HA), extracted from E. camaldulensis leaves, at three nominal concentrations, viz. 40, 120 and 360 mg C L^-1, replicated 4 times in the presence and absence of 30 µM Al. In the absence of Al, root elongation was increased by 30% by HA at 40 mg C L^-1 and by 36% by FA at 120 mg C L^-1. In the presence of 30 µM Al, the effects of toxic Al on root elongation were negated by FA and HA at all concentrations. Aluminium was totally complexed in all treatments except FA at 40 mg C L^-1 in which treatment only 2.7 µM Al was present in the monomeric form. The E. camaldulensis FA and HA at concentrations of 40 and 120 mg C L^-1, either in the presence or absence of Al, stimulated maize root elongation. Aluminium was strongly complexed by the E. camaldulensis FA and HA. The present results, in which FA and HA alleviated Al toxicity limitations on root elongation of maize, are relevant to the protection afforded to plant growth in acid soils amended with organic materials. They highlight the need to focus more on the role of FA and HA.     

Factors influencing fungal degradation of lignin in a representative lignocellulosic,thermomechanical pulp

This research examined culture parameters influencing the rate of degradation of lignin in lignocellulosic substrates by the Basidiomycete Phanerochaete chrysosporium. Thermomechanical pulps prepared from western hemlock (Tsuga heterophylla) and red alder (Alnus rubra) were chosen as model substrates. Degradation of lignin in shallow, liquid-phase, stationary cultures was 10 times as rapid as in agitated cultures. Lignin degradation was at least 50% more rapid in cultures under 100% O₂ than in those under air. Addition of 0.12% nutrient N (dry pulp basis) increased the rate of lignin degradation two- to fivefold; 1.2% added N at first suppressed, then stimulated, lignin degradation. Lignin in the alder pulp was degraded over five times as rapidly as in the hemlock pulp. Addition of glucose (35% of dry pulp) to the pulps containing 0.12% added N completely suppressed polysaccharide depletion during two weeks, but did not influence lignin degradation. The maximum rate of lignin degradation was 3%/day over a two-week incubation, or approximately 2.9 mg/mg fungal cell protein/day. The influence of the examined parameters was in complete accord with those found earlier for synthetic ¹⁴C-lignin metabolism by P. chrysosporium.     

Identification of low molecular weight aromatic compounds by gas chromatography–mass spectrometry (GC–MS) from kraft lignin degradation by three Bacillus sp.

Three bacterial strains identified as Paenibacillus sp., Aneurinibacillus aneurinilyticus and Bacillus sp. have been shown to decolourise kraft lignin in 6 days of incubation. The release of low molecular weight aromatic compounds by these bacterial strains during degradation of kraft lignin was analysed by GC–MS analysis. The total ion chromatograph (TIC) of ethyl acetate extract from kraft lignin sample inoculated by Paenibacillus sp. was similar to control except some minor changes in the chromatographic profile indicating incapability of this bacterium to modify kraft lignin. On the other hand the TIC of ethyl acetate extract from kraft lignin inoculated by A. aneurinilyticus and Bacillus sp. caused formation of several aromatic lignin-related compound that were not present in the extract of control. The compounds identified in extract of the sample degraded by A. aneurinilyticus were guaiacol, acetoguiacone, gallic acid and ferulic acid while t-cinnamic acid, 3,4,5 trimethoxy benzaldehyde, and ferulic acid by Bacillus sp. indicating oxidization of coniferylic (G units) and sinapylic (S units) alcohol of lignin polymer. Differences between the identified compounds from different bacterial treatment were strain-specific. Among the identified aromatic compounds, ferulic acid and 3,4,5-trimethoxy benzaldehyde could be useful to the industry of preservatives, aromas and perfumes.     

Red HE7B degradation using desulfonation by Pseudomonas desmolyticum NCIM 2112

Red HE7B (RHE7B, 100 mg l⁻¹), a sulfonated azo dye, was decolorized at static condition by Pseudomonas desmolyticum NCIM 2112 in 72 h with 71% reduction in chemical oxygen demand (COD). Extracellular lignin peroxidase (LiP) has played a crucial role in breakdown of the dye by asymmetric cleavage and reductases in the initial 24 h incubation to break azo bonds of some dye molecules. Dye also induced the activity of aminopyrine N-demethylase, one of the enzymes of mixed function oxidase system. Decolorization and degradation were analyzed by using UV–vis and high-pressure liquid chromatography (HPLC). The Fourier transform infrared spectroscopy (FTIR) analysis revealed that P. desmolyticum preferred C–N and SO bonds to break down the RHE7B. GC–MS identification of 8-amino-naphthalene-1,3,6,7-tetraol and 2-hydroxyl-6-oxalyl-benzoic acid as final metabolites supports the degradation of RHE7B by desulfonation before and after ring cleavage. Aerobic degradation of amines and reduced phytotoxicity increased the applicability of this microorganism for dye removal.

Scientific relevance of the paper

This is the first report on degradation of Red HE7B by oxidative enzymes and on further degradation by desulfonation before and after ring cleavage.     

一株3-苯氧基苯甲酸降解菌的筛选及其协同Bacillus licheniformis G-04降解高效氯氰菊酯的研究

【目的】从长期受拟除虫菊酯类农药污染的白菜根系土壤分离1株3-苯氧基苯甲酸(3-phenoxybenzoic acid, 3-PBA)降解菌,并探究其与Bacillus licheniformis G-04协同作用对高效氯氰菊酯(beta-cypermethrin,Beta-CP)的降解及污染土壤的生物修复,为土壤农药残留危害处理提供优良菌种。【方法】采用富集驯化、筛选纯化方法,筛选3-PBA降解菌,并通过形态和生理生化特征以及16S rRNA序列分析进行鉴定。利用Origin 8.0分析3-PBA降解菌与B. licheniformis G-04的生长降解动力学过程。同时,采用高效液相色谱法评估两菌株协同降解Beta-CP的能力及其对受Beta-CP污染土壤的修复作用。【结果】筛选得到1株3-PBA高效降解菌HA516,48 h对3-PBA (100 mg/L)的降解率达到87.73%,经鉴定为皮特不动杆菌(Acinetobacter pittii);构建了该菌株和B. licheniformis G-04的生长降解动力学方程,结果表明模型与实验数据能较好拟合;以6.7∶3.3的接种比例先接种B. licheniformis G-04,24 h后再接入A. pittii HA516协同作用,在48 h,Beta-CP (50 mg/L)的降解率达78.37%,较单菌株(B. licheniformisG-04)的降解率(40.47%)提高了37.90%,半衰期从58.39h缩短为24.51h。土壤修复实验表明,第7天协同组对Beta-CP(30mg/kg)的降解率较单菌株提高了33.26%,达到79.27%。【结论】A.pittiiHA516是1株3-PBA高效降解菌,能与B. licheniformis G-04协同增效降解Beta-CP,可作为修复3-PBA或拟除虫菊酯类农药污染的优良微生物资源。     

Biodegradation of 2,4,6-trinitrotoluene byPhanerochaete chrysosporium: Identification of initial degradation products and the discovery of a TNT metabolite that inhibits lignin peroxidases

Biodegradation of 2,4,6-trinitrotoluene (TNT) by the wood-rotting BasidiomycetePhanerochaete chrysosporium was studied in a fixed-film silicone membrane bioreactor and in agitated pellected cultures. The initial intermediate products of TNT biodegradation were shown to be 2-amino-4,6-dinitrotoluene (2amDNT) and 4-amino-2,6-dinitrotoluene (4amDNT). These intermediates were also degraded byP. chrysosporium. However, their rates of degradation were slow and appeared to represent rate-limiting steps in TNT degradation. The fact that 2amDNT and 4amDNT were further degraded is of importance. In most other microbial systems these compounds are typically not further degraded or are dimerized to even more persistent azo and azoxydimers. Similar to previous studies performed in stationary cultures, it was shown that substantial amounts of [¹⁴C]-TNT were degrade to [¹⁴C]-carbon dioxide in agitated pelleted cultures. Lignin peroxidase activity (assayed by veratryl alcohol oxidation) virtually disappeared upon addition of TNT to ligninolytic cultures ofP. chrysosporium. However, TNT, 2amDNT, and 4amDNT did not inhibit lignin peroxidase activity, nor were they substrates for this enzyme. Subsequent studies revealed that 4-hydroxylamino-2,6-dinitrotoluene, an intermediate in TNT reduction, was a potent lignin peroxidase inhibitor. Further studies revealed that this compound was also a substrate for lignin peroxidase H8.     

Protoplast Fusion between Geotrichum candidium and Phanerochaete chrysosporium to Produce Fusants for Corn Stover Fermentation

Lignin impedes the digestion of corn stover when used as an animal feed. Phanerochaete chrysosporium is an efficient lignindegrader. Geotrichum candidum can be used to produce single-cell protein. In this study, protoplasts of the two fungi were prepared and fused. After screening, one of the fusants, Fusant R1, was selected for corn stover fermentation. It decreased lignin from 109 to 54 g/kg and increased protein from 48 to 67 g/kg in corn stover. Comparison with their parental strains indicated that the fusant obtained the lignin-degrading ability from P. chrysosporium and the protein-accumulating ability from G. candidium.     

Production and Characterization of Polymeric Lignin Degradation Intermediates from Two Different Streptomyces spp.

Previous investigations have identified a quantitatively major intermediate of lignin degradation by Streptomyces viridosporus. The intermediate, a modified lignin polymer, acid-precipitable polymeric lignin (APPL), is released as a water-soluble catabolite and has been recovered in amounts equivalent to 30% of the lignin originally present in a corn stover lignocellulose substrate after degradation by this actinomycete. In the present work, APPLs were collected at various time intervals from cultures of two highly ligninolytic Streptomyces sp. strains, S. viridosporus T7A and S. badius 252, growing on corn stover lignocellulose. APPL production was measured over time, and the chemistry of APPLs produced by each organism after different time intervals was compared. Chemical characterizations included assays for lignin, carbohydrate, and ash contents, molecular weight distributions by gel permeation chromatography, and chemical degradation analyses by permanganate oxidation, acidolysis, and alkaline ester hydrolysis. Differences between the organisms were observed in the cultural conditions required for APPL production and in the time courses of APPL accumulation. S. viridosporus produced APPL in solid-state fermentation over a 6- to 8-week incubation period, whereas S. badius produced as much or more APPL, but only in liquid culture and over a 7- to 8-day incubation period. The chemistry of the APPLs produced also differed. S. viridosporus APPL was more lignin-like than that of S. badius and was slowly modified further over time, although no change in molecular weight distribution over time was observed. In contrast, S. badius APPL was less lignin-like and increased substantially in average molecular weight over time. Results indicated that differing mechanisms of lignin metabolism may exist in these two Streptomyces sp. strains. S. viridosporus APPL probably originates from the heart of the lignin and is released largely as the result of β-ether cleavage and other oxidative reactions. S. badius APPL probably originates in the same manner; however, after release as a water-soluble catabolite, lower-molecular-weight intermediates of lignin degradation are repolymerized with APPL in a reaction catalyzed by an extracellular phenol oxidase. The chemical analyses and the presence of extracellular phenol oxidase in S. badius, but not in S. viridosporus, support this conclusion.     

Experiences with the on-line measurement of culture fluorescence during cultivation of Bacillus subtilis, Escherichia coli and Sporotrichum thermophile

Bacillus subtilis and Escherichia coli K12 (both transformed for human leukocyte interferon production) and Escherichia coli B/r and Sporotrichum thermophile (a deuteromycete) were cultivated in submersed culture and the culture fluorescence recorded on-line using a fluorometer. During the cultivation of B. subtilis the signal from the fluorometer correlated with cell density and interferon production and thus could be used for process control (interferon production). However, the culture fluorescence of the other organisms did not increase (S. thermophile), was too weak to be measured with the fluorometer used (E. coli transformed for interferon production), or the signal from the fluorometer was not an accurate measure of the culture fluorescence because of the accumulation of a fluorophor in the culture medium (E. coli B/r).     

Catabolic Fate of Streptomyces viridosporus T7A-Produced, Acid-Precipitable Polymeric Lignin upon Incubation with Ligninolytic Streptomyces Species and Phanerochaete chrysosporium

Degradation of ground and hot-water-extracted corn stover (Zea mays) lignocellulose by Streptomyces viridosporus T7A generates a water-soluble lignin degradation intermediate termed acid-precipitable polymeric lignin (APPL). The further catabolism of T7A-APPL by S. viridosporus T7A, S. badius 252, and S. setonii 75Vi2 was followed for 3 weeks in aerated shake flask cultures at 37°C in a yeast extract-glucose medium containing 0.05% (wt/vol) T7A-APPL. APPL catabolism by Phanerochaete chrysosporium was followed in stationary cultures in a low-nitrogen medium containing 1% (wt/vol) glucose and 0.05% (wt/vol) T7A-APPL. Metabolism of the APPL was followed by turbidometric assay (600 nm) and by direct measurement of APPL recoverable from the medium. Accumulation and disappearance of soluble low-molecular-weight products of APPL catabolism were followed by gas-liquid chromatography and by high-pressure liquid chromatography, utilizing a diode array detector. Identified and quantified compounds present in culture media included p-coumaric acid, ferulic acid, p-hydroxybenzoic acid, p-hydroxybenzaldehyde, protocatechuic acid, vanillic acid, and vanillin. The further catabolism of these APPL-derived aromatic compounds varied with the culture examined, and only S. setonii and P. chrysosporium completely degraded all of them. Some new intermediates of APPL metabolism also appeared in culture media, but the patterns were culture specific. Additional evidence from high-pressure liquid chromatography analyses indicated that one strain, S. badius, converted a water-soluble fraction evident by high-pressure liquid chromatography (7 to 10 min retention time range) into new products appearing at shorter retention times. Mineralization of a [¹⁴C-lignin]APPL was also followed. The percent ¹⁴C recovered as ¹⁴CO₂, ¹⁴C-APPL, ¹⁴C-labeled water-soluble products, and cell mass-associated radioactivity, were determined for each microorganism after 1 and 3 weeks of incubation in bubbler tube cultures at 37°C. P. chrysosporium evolved the most ¹⁴CO₂ (10%), and S. viridosporus gave the greatest decrease in recoverable ¹⁴C-APPL (23%). The results show that S. badius was not able to significantly degrade the APPL, while the other microorganisms demonstrated various APPL-degrading abilities. The significance of these findings relative to the fate of APPLs in nature was discussed.     

氮素添加和功能群去除对糙隐子草和大针茅根系特征的影响

由于草地不合理利用,中国北方草原严重退化,导致生态系统结构性破坏甚至功能性紊乱。随着草原退化,中能值功能群植物糙隐子草会取代高能值功能群植物大针茅成为群落中优势度最大的植物。为了解大针茅和糙隐子草在氮素添加以及去除功能群的情况下根系特征的变化趋势,选取锡林郭勒盟典型草原中的退化草原群落,分别开展两项实验,实验1:氮素添加梯度实验(0、10.5、17.5、28 gN/m~2),实验2:同时进行功能群的去除和氮素的添加,功能群去除实验(将植物分为高能值植物功能群、中能值植物功能群、低能值植物功能群3个功能群;每个处理分别剪除另外两个功能群,留取单一功能群),并同时进行氮素添加实验(0、17.5 gN/m~2)。在进行两年的实验处理后,通过Delta-T SCAN根系分析仪测量大针茅和糙隐子草根系的长度、直径、面积、体积指标。分析植物根系对氮素添加的响应,以及功能群去除是否改变这两种植物对氮素添加的响应格局。实验1研究结果表明:在受到其他功能群的竞争压力下,大针茅根系长度、面积、体积均在高氮素添加(28 gN/m~2)情况下显著增加,糙隐子草根系直径和体积在中氮素添加(17.5 gN/m~2)的情况下显著高于其他3个处理,退化样地中土壤氮素的增加,促使大针茅根系主要通过增加根系长度扩大在土壤中的空间分布,而促使糙隐子草主要通过增粗生长来扩大土壤分布空间。实验2研究结果表明:功能群的去除,中氮素添加对根系的影响,只有糙隐子草的根系直径显著增加。综合来看,功能群去除实验对大针茅的根系长度和面积有影响,对糙隐子草的根系长度、直径和面积有影响。功能群去除处理与氮素添加的交互作用对大针茅根系没有影响,对糙隐子草的根系直径和体积有影响。     

Improvement of in-rumen digestibility of alfalfa forage by genetic manipulation of lignin O-methyltransferases

Lignin inhibits forage digestibility by ruminant animals, and lignin levels and the proportion of dimethylated syringyl (S) lignin monomers increase with progressive maturity in stems of forage crops. We generated transgenic alfalfa (Medicago sativa L.) with reduced lignin content and altered lignin composition. Down-regulation of caffeic acid 3-O-methyltransferase (COMT) reduces lignin content, accompanied by near total loss of S lignin, whereas down-regulation of caffeoyl coenzyme A 3-O-methyltransferase (CCoAOMT) reduces lignin content without reduction in S lignin. These changes are not accompanied by altered ratios of cell wall polysaccharides. Analysis of rumen digestibility of alfalfa forage in fistulated steers revealed improved digestibility of forage from COMT down-regulated plants, but a greater improvement in digestibility following down-regulation of CCoAOMT. The results indicate that both lignin content and composition affect digestibility of alfalfa forage, and reveal a new strategy for forage quality improvement by genetic manipulation of CCoAOMT expression.     

Lignin peroxidase production by strains of Phanerochaete chrysosporium grown on glycerol

Summary Lignin peroxidase production by several strains of Phanerochaete chrysosporium was determined during growth on glycerol under conditions of nitrogen sufficiency. Fungal strains which grew poorest on glycerol produced the highest titres of lignin peroxidase whereas enzyme levels were much lower when marginally greater biomass values were recorded. In the case of P. chrysosporium strain INA-12, the nature of the nitrogen source had a pronounced effect on both growth and enzyme production. Highest biomass values were obtained when l-glutamate or l-glutamine served as the major nitrogen source but enzyme synthesis was normally repressed completely. Lignin peroxidase activity in this strain was maximal when the initial pH of the culture medium was adjusted to pH 5.0.     

Topochemical investigation of early stages of lignin modification within individual cell wall layers of Scots pine (Pinus sylvestris L.) sapwood infected by the brown-rot fungus Antrodia vaillantii (DC.: Fr.) Ryv.

The initiation and progress of wood degradation of Pinus sylvestris sapwood exposed to the brown-rot fungus Antrodia vaillantii was studied on a cellular level by scanning UV microspectrophotometry (UMSP 80, Zeiss, MSP 800 Spectralytics). This improved analytical technique enables direct imaging of lignin modification within individual cell wall layers. The topochemical analyses were supplemented by light and transmission electron microscopy (TEM) studies in order to characterize morphological changes during the first days of degradation. Small wood blocks (1.5 × 1.5 × 5 mm) of Scots pine (P. sylvestris) were exposed to fungal decay by A. vaillantii for 3, 7, 11, 16, and 22 days. No significant weight loss was determined in the initial decay periods within three up to 7 days. After three days of decay the topochemical investigation revealed that the lignin modification starts at the outermost part of the secondary wall layer, especially in the region of the latewood tracheids. During advanced degradation after exposure of 22 days, lignin modification occurs non-homogeneously throughout the tissue. Even among the significantly damaged cells, some apparently unmodified cells still exist. Knowledge about lignin modification at initial stages of wood degradation is of fundamental importance to provide more information on the progress of brown-rot decay.     

Fatty acid composition of lipids from mushrooms belonging to the family Boletaceae

The non-polar lipid content and fatty acid (FA) composition of 11 mushroom species of the family Boletaceae were determined. The non-polar lipid content ranged from 2.0 (Leccinum aurantiacum and Boletus erythropus) to 5.4 % (w/w) d.w. (Suillus grevillei) with an average value of 2.9 %. More than 25 different FAs were found in the mushroom lipids. Unsaturated FAs, mainly linoleic and oleic acids, accounted for about 83 % of the total FAs, while palmitic acid was the main saturated FA. Some FAs are identified for the first time in Boletaceae and in higher Basidiomycetes (cis-11,12-methyleneoctadecanoic acid, 7-cis,10-cis hexadecadienoic) or in fungi (cis-11,12-methyleneoctadecanoic acid). There were significant differences (P < 0.05) in the contents of specific FAs between mushroom species.     

Use of diluted medium in repeated-batch fermentation for production of lignin peroxidase by <Emphasis Type="Italic">Phanerochaete chrysosporium</Emphasis>

Lignin peroxidase has been extensively studied due to the potential use of this enzyme in environmental pollution control. Important aspects of the production of the enzyme by the white rot fungus, Phanerochaete chrysosporium, include the improvement of yield results and cell maintenance. In the present work, Phanerochaete chrysosporium was immobilized in polyurethane foam and used for repeated-batch fermentations with various dilution of the initial medium (D), and lignin peroxidase production was investigated. The peak of 283 ± 17.5 U lignin peroxidase/l production rate was obtained at a D of 1/5, with significantly lower production rates seen at higher and lower dilution ratios. When six cycles of repeated-batch fermentation were conducted using a D of 1/5, the results revealed that at least four cycles of repeated-batch fermentation were possible with a high lignin peroxidase production rate under a cut-off value of 178 ± 3.87 U/l. Furthermore, the cell-free culture broth could be successfully concentrated to 2,800 U/l by ultrafiltration. Thus, the present study shows that optimizing the dilution of the utilized nutritional medium can improve repeated batch production of lignin peroxidase from immobilized P. chrysosporium, in terms of both cycle number and output.     

Degradation of synthetic lignin by the protoplasts of Phanerochaete chrysosporium in the presence of lignin peroxidase or manganese peroxidase

Lignin was mineralized in the experiments in which ¹⁴C-lignin was incubated with lignin peroxidase or manganese peroxidase in a tartrate buffer in the presence of cycloheximide-treated protoplasts obtained from the ligninolytic mycelia of Phanerochaete chrysosporium. The rate of lignin mineralization was dependent on the lignin peroxidase or manganese peroxidase concentration in the medium. In the experiments in which lignin was incubated with lignin peroxidase or manganese peroxidase, lignin was repolymerized irrespective of the presence of protoplasts mineralizing lignin, suggesting that an active degradation of lignin and repolymerization took place. Taking into account that lignin peroxidase and manganese peroxidase were the only extracellular enzymes in the experiments in which lignin was mineralized by the protoplasts, it is postulated that lignin peroxidase and/or manganese peroxidase can degrade lignin into small fragments which can then be further absorbed by the fungal cells and subsequently degraded to CO₂.     

微泡菌属菌株YPW1和YPW16多糖降解特性分析

【背景】海洋环境中分离到的微泡菌属菌株具有多糖降解能力,在环境中可以作为糖类代谢的重要执行者参与海洋碳循环过程。【目的】测定2株微泡菌属菌株的多糖降解活性,通过与微泡菌属其他菌株基因组比较分析2株菌的多糖降解基因特征。【方法】通过3,5-dinitrosalicylicacid(DNS)定糖法测定多糖降解活性,同时利用高通量测序技术对菌株基因组序列进行测定与组装,并与其他基因组注释结果进行比较分析。【结果】分离得到2株微泡菌属菌株YPW1和YPW16,二者均为潜在新种。结果表明,菌株YPW1能够降解琼胶、褐藻胶、果胶、几丁质、木聚糖、淀粉、普鲁兰等7种多糖,而菌株YPW16仅可降解淀粉和普鲁兰。基因组分析表明,YPW1具有上述7种多糖的降解酶基因,但菌株YPW16只具有淀粉酶与普鲁兰酶降解基因。相较于其他微泡菌属菌株,菌株YPW1多糖降解范围、多糖降解酶基因种类与丰度较高,但菌株YPW16多糖降解范围却较为狭窄。由此可知,多糖降解酶基因在微泡菌属基因组中的分布差异性较大。【结论】本研究为微泡菌属提供了2株潜在的新型菌株资源,为生物多糖降解提供了生化工具,也为研究微泡菌属菌株中多糖降解基...     

New species of Phaeoramularia, Pseudocercospora and Stenella from Western Ghats of India

Four new species of the hyphomycete genera Phaeoramularia viz. Ph. caesalpinae, Pseudocercospora viz., Ps. tiliacearum, Stenella, viz. S. argyreiae and S. grewiae occurring on Caesalpinia bonducella Fleming (Caesalpiniaceae), Grewia sp. (Tiliaceae), Argyrea sp. Lour (Convolvulaceae) and Grewia sp. L. (Tiliaceae), respectively are described and illustrated here. All these fungi were collected from Western Ghats of India.