Highest Laccase Research Articles

Induced mutation in Agaricus bisporus by gamma ray to improve genetic variability, degradation enzyme activity, and yield

Purpose Genetic variability in white button mushroom cultivars is very low due to the life cycle. Induction mutations using gamma irradiation is a useful way to generate diversity in white button mushrooms to obtain genotype(s) with desirable traits. Methods Gamma irradiation Cobalt-60 was used for inducting genetic diversity in white button mushroom to obtain genotype(s) with desirable traits. Gamma irradiation with doses of 0-500 Gy was conducted on spores on Potato Dextrose Agar medium. Results The results showed significant differences in days to pin production and harvest, fruit body number, fresh and dry weight, yield, laccase, and manganese peroxidase enzyme activity. After isolating variants, 15 variants were selected on the base of their high yield and enzyme degradation activity. Their genetic variation was confirmed by Sequence Related Amplified Polymorphism (SRAP) markers, and then incubated on three types of substrates (50:50, 75:25, and 100:0 % compost: raw straw). The results showed that all variants, except GR18, colonized in 75:25, and GR3, GR4, GR9, GR61, GR72, and GR74 variants colonized in 50:50. In 100:0 substrate, GR55 and GR63 were the earliest variants, and GR9 produced the highest fruit body number. In 75:25 substrate, GR9, GR3, GR61, GR4, GR74, GR4, GR61, and GR72 showed higher yields. The highest laccase and manganese peroxidase activity were recorded in GR3, GR4, GR9, GR72, and GR61. The isolated 15 variants were clustered into two main groups by cluster analysis and genetic variation was confirmed by SRAP markers. Conclusion The results showed that the diversity in the white button mushroom could be improved using gamma rays, and the variation would be useful for the development of future breeding programs.

Fabrication of hollow covalent-organic framework microspheres via emulsion-interfacial strategy to enhance laccase immobilization for tetracycline degradation

• Hollow microspheres H-COF-OMe were prepared by emulsion interfacial polymerization. • Interfacial-defects in H-COF-OMe were formed by confined growth on emulsion droplets. • Lac@H-COF-OMe showed both high laccase loading and activity recovery. • Lac@H-COF-OMe displayed excellent structure stability and recyclability. • Lac@H-COF-OMe exhibited better adsorption uptake and faster degradation rate for tetracycline. Hollow covalent organic framework microsphere (H-COF-OMe) using TAPB and DMTP with enriched interfacial defects was fabricated via emulsion interfacial polymerization and in turn applied as a novel host for high laccase loading and tetracycline (TC) degradation. Benefited from the space-confined growth in the multiphase solvent interface, H-COF-OMe exhibited hollow spherical microstructure, high surface area and unique defects-rich interface. Attributed to these intriguing aspects, H-COF-OMe achieved maximum loading capacity of 567 mg/g and activity recovery of 85% for laccase. H-COF-OMe efficiently stabilized the active conformation of laccase from structural distortion via multiple binding sites, which endowed Lac@H-COF-OMe significantly higher pH, thermal, and storage stabilities, and reusability than free laccase and Lac@COF-OMe. Interestingly, the hollow morphology and defective interface of Lac@H-COF-OMe accelerated the diffusion of TC and shortened the reaction pathway, which endowed it with markedly enhanced TC degradation and recycling performance than many state-of-the-art catalysts. Significantly, Lac@H-COF-OMe (20 mg) could achieve 99% degradation of 50 mg/L tetracycline (50 mL) within 100 min. Monitoring of the intermediate products indicated that Lac@H-COF-OMe showed outstanding detoxification performance of the degradation products. This work suggested a novel COF synthesis strategy as laccase immobilization supporters for high TC degradation, which makes it as a promising candidate for degradation of organic pollutants.

Evaluation of Laccase Production by Monokaryotic Strains of Edible Mushrooms.

<b>Background and Objective:</b> Edible mushroom laccases are one of the most attractive enzymes applicable in numerous industrial sectors. The purpose of this research is to construct monokaryotic strains from selected isolates of edible mushrooms and to study the effects of inducers on laccase production under solid-state fermentation. <b>Materials and Methods:</b> Isolation of local commercial strains of edible mushrooms was carried out from the pileus region using standard laboratory techniques. The laccase production was carried out using 40 mM 2,6-Dimethoxyphenol (2,6-DMP) and 40 mM guaiacol as substrate. The generation of monokaryotic strains was performed by mycelium homogenization in sterile water and regrowth in an appropriate medium. Laccase production and study of the effects of inducers on laccase production were then studied. <b>Results:</b> Laccase production of native and monokaryotic strains distinguished these strains into three groups: HIGH-(KK24, KK25), MEDIUM-(KK26, KK1, KK5 and KK23) and LOW (KK13, KK8). Reduced activity was found in almost all isolates after 14 days of inoculation. The effect of pure copper sulfate, copper sulfate with DMP, Tween80 and synthetic melanoidin was studied at 7 and 14 days. KK24 and KK25 showed their positive response to all inducers about 1.5-2.5 folds of activity to their native strains. <b>Conclusion:</b> Eight strains of local and commercial mushrooms were isolated and purified. The corresponding monokaryotic strains were generated from chemical dedikaryotization. Studies of laccase production showed that KK24 and KK25 were high laccase producer's throughout the incubation period. The addition of inducers augmented laccase activity in KK24 and KK25 along with their corresponding monokaryotic strains.

Characterization of a Novel Laccase LAC-Yang1 from White-Rot Fungus Pleurotus ostreatus Strain Yang1 with a Strong Ability to Degrade and Detoxify Chlorophenols.

In this study, a laccase LAC-Yang1 was successfully purified from a white-rot fungus strain Pleurotus ostreatus strain yang1 with high laccase activity. The enzymatic properties of LAC-Yang1 and its ability to degrade and detoxify chlorophenols such as 2,6-dichlorophenol and 2,3,6-trichlorophenol were systematically studied. LAC-Yang1 showed a strong tolerance to extremely acidic conditions and strong stability under strong alkaline conditions (pH 9–12). LAC-Yang1 also exhibited a strong tolerance to different inhibitors (EDTA, SDS), metal ions (Mn2+, Cu2+, Mg2+, Na+, K+, Zn2+, Al3+, Co2+, and metal ion mixtures), and organic solvents (glycerol, propylene glycol). LAC-Yang1 showed good stability in the presence of Mg2+, Mn2+, glycerol, and ethylene glycol. Our results reveal the strong degradation ability of this laccase for high concentrations of chlorophenols (especially 2,6-dichlorophenol) and chlorophenol mixtures (2,6-dichlorophenol + 2,3,6-trichlorophenol). LAC-Yang1 displayed a strong tolerance toward a variety of metal ions (Na2+, Zn2+, Mn2+, Mg2+, K+ and metal ion mixtures) and organic solvents (glycerol, ethylene glycol) in its degradation of 2,6-dichlorophenol and 2,3,6-trichlorophenol. The phytotoxicity of 2,6-dichlorophenol treated by LAC-Yang1 was significantly reduced or eliminated. LAC-Yang1 demonstrated a good detoxification effect on 2,6-dichlorophenol while degrading this compound. In conclusion, LAC-Yang1 purified from Pleurotus ostreatus has great application value and potential in environmental biotechnology, especially the efficient degradation and detoxification of chlorophenols.

Optimization of growth conditions for enhancing the production of microbial laccase and its application in treating antibiotic contamination in wastewater.

In this work, seven indigenous macrofungal isolates were selected to screen for their laccase production capability. Among them, isolates viz., Pleurotus eryngii, Pleurotus florida, Pleurotus sajor caju and Gandoderma lucidum were found to exhibit high laccase activity in the preliminary studies and were thus selected for the optimization studies with an aim to enhance laccase production. The pH optimization studies were carried out between pH range of 4-6. The laccase activity and biomass were found to be optimum at pH 4, 4.5, 4.5 and 5 for P. eryngii, P. florida, P. sajor caju and G. lucidum, respectively. Optimization studies with chemical inducers namely, tannic acid, 2,6 dimethoxyphenol and copper sulphate at three different concentration levels were conducted and tannic acid at 2mM concentration was found to increase the laccase activity to about 45% followed by 2,6 dimethoxyphenol (2mM) with an increase of about 43% and copper sulphate (0.1mM) showing 21% increase in the yield. Biodegradation studies utilizing laccase isolated from P. eryngii, P. florida and P. sajor caju was carried out for a commonly detected fluoroquinolone antibiotic, levofloxacin, in water and pharmaceutical wastewater. The results indicated that the degradation efficiency of levofloxacin using laccase isolated from P. eryngii (88.9%) was comparable to commercial laccase (89%). When the cost economics of using crude laccase was evaluated against commercial laccase it was evident that the total cost of the treatment could be reduced by 71.7% if commercial grade laccase was replaced by crude enzyme extracted from indigenous macrofungi such Pleurotus eryngii, Pleurotus florida, and Pleurotus sajor caju indicating a promising and cost-effective alternative for wastewater treatment.

Study of Production and Characterization of Laccase Enzyme from Klebsiellapneumoniae K7 Isolate

Sixty four local isolated of Klebsiella spp. have been isolated from environment samples (soil and water).These isolates were identified and diagnosis according to phenotype and biochemical tests. These isolateswere subjected to primary and secondary screening, to select the isolate with the highest laccase activity.Fifteen isolates chosen from primary screening for screening their enzyme activity in secondary screening.It has been found the Klebsiella(K7) has the highest productivity of the enzyme (12 Unit/ml).Klebsiella(K7)isolate was diagnosis by Vitak 2 system, it was identified asK. pneumonia. The laccase purified wascharacterization, the experiments showed that: The molecular weight of laccase was 120KD and the optimumpH for the purified laccase activity was 4.5 and forstability was 6.5. the optimum temperature for enzymeactivity was 40oC,the enzyme showed that laccase lost 22, 23 and 20% of its initial activity at 20, 25 and35°C, respectively.

Produção de biomassa micelial e enzimas lignocelulolíticas de Pleurotus spp. em meio de cultivo líquido

Pleurotus spp. são fungos capazes de degradar a lignocelulose graças à excreção de enzimas com diferentes aplicações industriais. O objetivo deste estudo foi avaliar a influência dos meios de cultivo na produção de biomassa micelial e na atividade de lacase, celulases e xilanase de Pleurotus spp. Pleurotus citrinopileatus U16-23, P. djamor U16-20, U16-25 e U16-28, P. eryngii U16-30, P. ostreatus U16-22 e P. pulmonarius U16-21 foram cultivados por 12 dias a 28 ºC em meio extrato de malte (EM-20 g L-1), meio definido (MD glicose 10 g L-1 e extrato de levedura 2 g L-1), ou em meio bagaço de cana-de-açúcar (BC) igual ao MD, mas substituindo glicose por bagaço (50 g L-1). O maior crescimento ocorreu no meio EM e P. djamor U16-25 a cepa que gerou mais biomassa (7,5 ± 0,1 g L-1). A maioria das cepas apresentou maior atividade de lacase no meio MD e as atividades maiores foram de P. djamor U16-25 (22243 ± 745 U L-1) e P. pulmonarius (20924 ± 46 U L-1). P. citrinopileatus e P. djamor U16-25 não produziram celulases, mas P. djamor U16-20 e P. eryngii produziram as maiores atividades de celulase nos meios EM e MD. Todas as cepas produziram xilanase em e as maiores atividades foram observadas no meio EM e P. djamor U16-28 (67154 ± 1597 U L-1) foi o maior produtor. Pleurotus djamor U16-25 se destacou como produtor de lacase e de xilanase livre de celulase revelando potencial para aplicação na indústria de papel e celulose.

Pola Aktivitas Enzim Lakase, Selulase, dan Xilanase Pada Masa Pertumbuhan Budidaya Jamur Tiram Putih [Pleurotus ostreatus (Jacq.) P. Kumm.

Recently, Pleurotus ostreatus has become the most cultivated edible mushroom in Indonesia because of the simple in cultivation. Pleurotus ostreatus easy to grow in a medium contained sawdust as a main substrate, with the addition of rice brand, corn flour, lime and gypsum. Mushroom production is bioconversion process which involves the activity of lignocellulolytic enzymes such as laccase, cellulase, and xylanase. The aim of this study was to reveal the pattern of laccase, cellulase, and xylanase activity during the growth of P. ostreatus on the sawdust medium. The results show that the highest laccase activity was obtained on the 15th day after spawn inoculation (ASI) of 0.66 Unit and decline sharply after the day of 45th ASI until the day of 75th ASI. Furthermore, the similar pattern with difference on the time incubation was obtained on the activity of cellulase and xylanase. It was decrease after the day 30th ASI. The highest activity of cellulase was 0.51 Unit on 30th day of ASI and decrease gradually until the day of 75th ASI. Furthermore, the highest activity of xylanase was on 30th day ASI of 0.34 Unit and decrease sharply until the day of 75th.

Construction and characterization of sandwich-type laccase electrode based on functionalized conducting polymers

Laccase (Lac) is a multi-active-center glycoprotein. Its heterogeneous electron transfer efficiency depends on the distance between the substrate binding site and the electrode surface. Laccase encapsulation by conducting polymers should be favorable for the direct electron transfer (DET) process, thus improving the electrocatalytic efficiency of the laccase electrode. Here, a sandwich-type laccase electrode based on functionalized conducting polymers was developed. First, porous poly (3-aminophenylboronic acid) (PAPBA) conductive film was electrodeposited on a glassy carbon electrode (GCE), and on which laccase was then immobilized via the specific binding of the boronic acid group from PAPBA and the glycosyl group on laccase. In addition to higher laccase loading, the present Lac/PAPBA/GCE electrode is more robust than that prepared by physical adsorption of laccase on conducting polymer. For laccase to be wired better, a poly (3,4-ethylenedioxythiophene) (PEDOT) conductive film with polystyrenesulfonate anion (PSS−) as dopant was electrochemically covered on the Lac/PAPBA/GCE. In addition to the compatibility among the stability of the cyclic boronic acid ester, the biological activity of the laccase, and the polymer conductivity, the sandwich-type laccase electrode was demonstrated to be more efficient than the counterpart without the second layer for the electroreduction of O2 probably due to a so-called “cage effect”. The "cage effect" of the sandwich-type conducting polymers reduces the requirement for laccase orientation and greatly improves the electrocatalytic performance of the laccase electrode.

Effects of dietary laccase supplementation on growth performance, nutrient digestion, rumen fermentation and microbiota in dairy bulls

This study investigated the impacts of dietary laccase addition on performance, nutrient digestion, rumen fermentation and microbiota in bulls. Eight Holstein bulls with rumen cannula were allocated in a repeated 4 × 4 Latin square experiment design into four groups: control, low-laccase (LL), medium-laccase (ML) and high-laccase (HL) with 0, 0.2, 0.4 and 0.6 g/kg dietary dry matter (DM) of laccase addition, respectively. Addition of laccase did not influence DM intake but higher average daily gain and lower feed conversion ratio were found for bulls in ML group. Apparent nutrients digestibility elevated linearly with increasing laccase supplementation. Digestibility of DM and organic matter in ML, crude protein (CP) in ML and HL as well as neutral detergent fibre (NDF) and acid detergent fibre in LL, ML and HL were higher. Increasing laccase addition quadratically decreased ruminal pH, quadratically increased total volatile fatty acids content and changed ruminal fermentation mode to more propionate formation. Ruminal ammonia-N concentration decreased linearly. Ruminal degradability of concentrate CP and corn silage DM were higher for bulls in ML, but degradability of corn silage NDF was higher for bulls in ML and HL groups. Activities of cellobiase, α-amylase and laccase were higher for bulls in ML group. Populations of total bacteria, methanogens, Fibrobacter succinogenes, Ruminococcus albus, Butyrivibrio fibrisolvens, Prevotella ruminicola and Ruminobacter amylophilus increased linearly, but fungi and R. flavefaciens increased quadratically. Urine excretion of total purine derivatives was higher for bulls receiving medium or high level of laccase supplementation. The results suggested that dietary laccase supplementation increased performance and nutrient digestibility, and the appropriate addition level of laccase was 0.4 g/kg DM in bulls.

Biodegradation of polycyclic aromatic hydrocarbons by high-laccase basidiomycetes fungi isolated from tropical forest of Borneo

Abstract A total of 804 fungi isolate were subjected to the screening of high laccase activity by four different indicators test, Poly R-478, RBBR, guaiacol, and syringaldazine. The results presented the diversity of 6 order, belonging to 17 families, 25 genera and 29 species, and most of the isolated strain was reacted with laccase chemical indicators and categorized as saprophytic, parasitic and ectomycorrhizal. Three fungi (Coriolopsis caperata, Fomes fomentarius, Pluteus chysophaeus) that isolated from Niah National Park and Lambir Hill National Park were selected for further experiment due to their high positive reaction on all tested indicators. The maximum level on the laccase production during fungi exponential growth was impacted by the addition of carbon source. Diphenic acid, 1-hydroxy-2naphthoic acid, catechol, and salicylic acid, anthraquinone, benzoic acid, and phthalic acid were detected as metabolites of phenanthrene, anthracene, and pyrene.

The Study of the Oxidation of N,N,N',N'-Tetramethyl-p-Phenylenediamine for the Clarification of the Differences in the Mechanisms of Biocatalytic and Chemical Polymerization of Aniline

The oxidation of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) using ammonium peroxydisulfate and the high redox potential laccase from Trametes hirsuta is studied in order to clarify the significant differences in the chemical and enzymatic polymerization reactions of aniline. As opposed to the laccase-catalyzed reaction, the chemical oxidation of TMPD proceeds in two stages. The radical cation formed at the first stage is oxidized by the peroxydisulfate ion to quinoiddiimine that can interact with the initial TMPD. The kinetics of the formation of the radical cation $${\text{TMP}}{{{\text{D}}}^{{\centerdot + }}}$$ is studied by ultraviolet–visible (UV–Vis) and electron paramagnetic resonance spectroscopy. The obtained data allow making an assumption about the difference in the mechanisms of chemical and enzymatic polymerization of aniline.

A novel lignin degradation bacteria-Bacillus amyloliquefaciens SL-7 used to degrade straw lignin efficiently

Using tobacco straw (Ts) and lignin as the sole carbon source, a strain was isolated from Ts and identified as Bacillus amyloliquefaciens SL-7 by 16S rDNA gene-sequencing technology.7-day incubation of Bacillus amyloliquefaciens SL-7 can reduce the chemical oxygen demand (COD) by 69.35% in lignin mineral salt medium. The activity of Manganese peroxidase (MnP) reached maximum level 258.57 U L−1, and Lignin peroxidase (Lip) was 422.68 U L−1 at 4th day. The highest Laccase (Lac) activity (55.95 U L−1) was observed at 3th day. After straw-liquid fermentation degradation of 15 days, the bacterial could degrade 28.55% lignin of the straw which was close to that of fungi. Compared with the control group and effective microorganisms (EM) group, the lignin degradation rate in Bacillus amyloliquefaciens SL-7 group increased by 22.26% and 11.70% at 41-day compost fermentation of tobacco straw. These show the strain has strong lignin degradation performance.

Extracellular Soil Enzyme Activities in High-Elevation Mixed Red Spruce Forests in Central Appalachia, U.S.A.

Anthropogenic emissions have impacted terrestrial forest ecosystem processes in North America since the industrial revolution. With the passage of the Clean Air Act in 1970 in the United States, atmospheric inputs of nitrogen (N) and sulfur (S) into forests in the Appalachian Mountains have declined, which have, potentially, mitigated their effects on processes such as decomposition and nutrient cycling. Activities of microbial extracellular soil enzymes (ESEs) mediate many rate-limiting nutrient transformations in forest soils and play important roles in the decomposition of complex organic compounds. Soils in high-elevation red spruce forests are characterized by low pH and high carbon (C):N ratios and, having historically received extremely high levels of N deposition, may exhibit legacy impacts of deposition on nutrient availability and decomposition. We utilized four sites along a modeled gradient of N deposition in central Appalachia to assess contemporary ESEs in bulk soil under Acer rubrum L., Betula alleghaniensis Britt., and Picea rubens Sarg. in May, June, and July 2016. Increasing N deposition led to increases in organic fraction C and N and decreases in phosphorus (P). Sites receiving higher N also exhibited greater mineral fraction C, N, and P. ESEs were highest in organic fractions with acid phosphatases (AP) exhibiting the highest activity. There was little influence of N deposition on organic fraction ESEs, but strong evidence for a positive relationship between N deposition and activities of AP, β-glucosidases (BG), and chitinase (NAG) in mineral fractions. Species effects on ESEs were present with high AP in organic fractions under spruce and high mineral fraction fungal laccase (LAC) under birch. The sampling season demonstrated little effect on ESEs. ESEs were more strongly influenced by plot-level factors, such as tree species diversity and abundance of ectomycorrhizal (ECM) tree species, than temporal or soil factors or nutrient status related to modeled cumulative N deposition across these sites. Decreases in AP, BG, and NAG activities with greater abundance of broadleaf deciduous species and increases in activities with ECM host abundance indicate that microbial communities driven by these plant functional groups are responsible for the differences in ESEs observed in these high-elevation mixed red spruce stands.

Enzyme Activity Profiles Produced on Wood and Straw by Four Fungi of Different Decay Strategies.

Four well-studied saprotrophic Basidiomycota Agaricomycetes species with different decay strategies were cultivated on solid lignocellulose substrates to compare their extracellular decomposing carbohydrate-active and lignin-attacking enzyme production profiles. Two Polyporales species, the white rot fungus Phlebia radiata and brown rot fungus Fomitopsis pinicola, as well as one Agaricales species, the intermediate “grey” rot fungus Schizophyllum commune, were cultivated on birch wood pieces for 12 weeks, whereas the second Agaricales species, the litter-decomposing fungus Coprinopsis cinerea was cultivated on barley straw for 6 weeks under laboratory conditions. During 3 months of growth on birch wood, only the white rot fungus P. radiata produced high laccase and MnP activities. The brown rot fungus F. pinicola demonstrated notable production of xylanase activity up to 43 nkat/mL on birch wood, together with moderate β-glucosidase and endoglucanase cellulolytic activities. The intermediate rot fungus S. commune was the strongest producer of β-glucosidase with activities up to 54 nkat/mL, and a notable producer of xylanase activity, even up to 620 nkat/mL, on birch wood. Low lignin-attacking but moderate activities against cellulose and hemicellulose were observed with the litter-decomposer C. cinerea on barley straw. Overall, our results imply that plant cell wall decomposition ability of taxonomically and ecologically divergent fungi is in line with their enzymatic decay strategy, which is fundamental in understanding their physiology and potential for biotechnological applications.

Soil and entomopathogenic fungi with potential for biodegradation of insecticides: degradation of flubendiamide in vivo by fungi and in vitro by laccase

PurposeFlubendiamide is a highly toxic and persistent insecticide that causes loss of insect muscle functions leading to paralysis and death. The objective was to screen for filamentous fungi in soils where insecticides had been applied, to isolate entomopathogenic fungi from insect larva (Anticarsia gemmatalis) that infest soybean crops, and to use these in biodegradation of insecticides.MethodFilamentous fungi were isolated from soils, and growth inhibition was evaluated on solid medium containing commercial insecticides, Belt® (flubendiamide) and Actara® (thiamethoxam). A total of 133 fungi were isolated from soil and 80 entomopathogenic fungi from insect larva. Based on growth inhibition tests, ten soil fungi, 2 entomopathogenic fungi, and Botryosphaeria rhodina MAMB-05 (reference standard) were selected for growth on commercial insecticides in solid media. Fungi were grown in submerged fermentation on media containing commercial insecticides and assayed for laccase activity.ResultIsolates JUSOLCL039 (soil), JUANT070 (insect), and MAMB-05 performed best, and were respectively inhibited by 48.41%, 75.97%, and 79.23% when cultivated on 35 g/L Actara®, and 0.0, 5.42%, and 43.39% on 39.04 g/L Belt®. JUSOLCL039 and JUANT070 were molecularly identified as Trichoderma koningiopsis and Neurospora sp., respectively. The three fungal isolates produced laccase constitutively, albeit at low activities. Fungal growth on pure flubendiamide and thiamethoxam resulted in only thiamethoxam inducing high laccase titers (10.16 U/mL) by JUANT070. Neurospora sp. and B. rhodina degraded flubendiamide by 27.4% and 9.5% in vivo, while a crude laccase from B. rhodina degraded flubendiamide by 20.2% in vitro.ConclusionThis is the first report of fungi capable of degrading flubendiamide, which have applications in bioremediation.

Laccase-Mediator Systems as a Tool for the Development of Antistatic/Anticorrosion Protective Coatings Based on Conducting Polyaniline

Template polymerization of aniline was performed using a laccase-mediator system. The high redox-potential laccase from the basidiomycete fungus Trametes hirsuta was a catalyst for polymerization. The aniline dimer served as the redox mediator; atmospheric oxygen served as the oxidant. Sodium dodecylbenzenesulfonate micelles were used as a “soft” template. The biocatalytic polymerization of aniline resulted in conducting polyaniline/sodium dodecylbenzene sulfonate complex that was tested as a protective coating. The efficiency of the inhibition of copper corrosion by the complex was 86–87%, and the dissipation rate of positive and negative charges from cotton fabrics increased by 56 and 27 times, respectively.

Bioethanol production from rice straw through an enzymatic route mediated by enzymes developed in-house from Aspergillus fumigatus

This study concerns the in-house development of enzymes from Aspergillus fumigatus and their application in separate hydrolysis and fermentation (SHF) processes for bioethanol production from pretreated rice straw. The cellulase and hemicellulase activities of A. fumigatus cultivated in NaOH-pretreated rice straw were much higher than those of A. fumigatus cultivated in raw rice straw. A. fumigatus cultivated in raw rice straw exhibited no lignin-degrading manganese peroxidase (MnP) or laccase enzymatic activity. However, A. fumigatus cultivated in NaOH-pretreated rice straw exhibited high lignin-degrading MnP and laccase enzymatic activity. A. fumigatus completely degraded 1.0% NaOH-pretreated rice straw, yielding 27.89 g/L reducing sugar upon loading of 50 g/L rice straw (based on the original amount of rice straw that went to pretreatment). Saccharification of 1.0% NaOH-pretreated rice straw using 200 FPU/mL crude enzyme released 22.15 g/L reducing sugars in 20 h. The SHF processes resulted in an ethanol concentration and yield of 9.45 g/L and 83.5%, respectively, with Saccharomyces tanninophilus.

The quest for fungal strains and their co-culture potential to improve enzymatic degradation of Chinese distillers’ grain and other agricultural wastes

Distillers’ grain (DG) is one of the lignocellulosic agricultural waste streams having a high potential for biofuel production, however it is causing health and environmental problems in Southwest region of China because of improper treatment before being used for landfill. Here, we aimed to identify fungal strains that efficiently hydrolyze DG and explored the possibility to further improve the hydrolysis of DG and other agricultural wastes by co-culturing these fungi. The tested fungal strains included 11 strains that were isolated from DG (Maotai Town, Guizhou, China) and 19 strains that were selected from the CBS collection of Westerdijk Fungal Biodiversity Institute. Aspergillus niger CBS 110.42 and CBS 554.65 and Phanerochaete chrysosporium CBS 246.84 showed overall best cellulose and xylan degrading activity, whereas high laccase and peroxidase activities were detected for Oidiodendron echinulatum CBS 113.65 and Bjerkandera adusta CBS 143380, respectively. Furthermore, A. niger CBS 554.65 co-cultured with Trichoderma reesei CBS 383.78 and A. niger CBS 110.42 with P. chrysosporium CBS 246.84 showed the best improvement (up to 2- and 3-fold higher of β-glucosidase and β-xylosidase activities). These fungi and the combinations have strong potential to be further developed for local bioenergy production.

Laser Mutagenesis of Phellinus igniarius Protoplasts for the Selective Breeding of Strains with High Laccase Activity.

Phellinus igniarius is a medicinal fungus that utilizes lignin as a nutrient substrate. This fungus has a weak lignin degradation ability and, as a result, a slow growth rate. Laccases are crucial enzymes for lignin degradation in P. igniarius, and thus, the cultivation of strains with high laccase activity is expected to increase the growth rate of P. igniarius. To generate P. igniarius strains with high laccase activity, we performed laser mutagenesis of P. igniarius protoplasts and screened for mutants with high laccase activity. Our results showed that the laser power density and P. igniarius protoplast survival rate exhibited a power-function relationship. The power density threshold value between lethality and growth promotion was 0.24mW/mm2. Mutagenesis was carried out using a laser beam diameter of 3mm and an irradiation period of 40min. After five generations of selection, we identified a high laccase activity strain, termed SJZ2. The laccase activity in SJZ2 during 4h of fermentation was increased by 36.84% in comparison with the control and ranged from 0.20216 to 0.27664U. The Km and Vmax of the laccase produced by SJZ2 were 0.21mmol/mL and 0.53mmol/L/min, respectively. This study demonstrated the feasibility of laser mutagenesis of P. igniarius protoplasts for the selection of high laccase activity. This study characterized the key factors in the laser mutagenesis process of P. igniarius protoplasts and provided a reference for the application of lasers in biological mutagenesis. Future studies should evaluate the bioactive functionality and stability of this novel strain of P. igniarius, particularly the organoleptic and medical characteristics of the fruiting bodies.