Laccase Activity Research Articles

Influence of the agrochemical benomyl on Cryptococcus gattii-plant interaction in vitro and in vivo.

Cryptococcus gattii, an environmental fungus, is one of the agents of cryptococcosis. The influence of agrochemicals on fungal resistance to antifungals is widely discussed. However, the effects of benomyl (BEN) on fungal interaction with different hosts is still to be understood. Here we studied the influence of adaptation to BEN in the interaction with a plant model, phagocytes and with Tenebrio molitor. First, the strain C. gattii L24/01 non-adapted (NA), adapted (A) to BEN, and adapted with further culture on drug-free media (10p) interact with Nicotiana benthamiana, with a peak in the yeast burden on the 7th day post-inoculation. C. gattii L24/01 A and 10p provided lower fungal burden, but these strains increased cell diameter and capsular thickness after the interaction, together with decreased fungal growth. The strains NA and A showed reduced ergosterol levels, while 10p exhibited increased activity of laccase and urease. L24/01 A recovered from N. benthamiana was less engulfed by murine macrophages, with lower production of reactive oxygen species. This phenotype was accompanied by increased ability of this strain to grow inside macrophages. Otherwise, L24/01 A showed reduced virulence in the T. molitor larvae model. Here, we demonstrate that the exposure to BEN, and interaction with plants interfere in the morphophysiology and virulence of the C. gattii.

Ферменты биомассы мицелия грибов Cordyceps militaris и Lentinula edodes в технологии хлеба

Cordyceps militaris and Lentinula edodes are known for their high extracellular proteolytic, amylolytic, and laccase activity, which is important for bakery production. This article describes the effect of enzymes obtained from mycelial biomass of C. militaris and L. edodes on such properties of flour mixes as amylolytic and proteolytic enzymic activity during baking, technological costs, and bread quality. The research featured strains of C. militaris SRG4 and L. edodes 3790 fungi; mycelial biomass powder of these fungi on a sterile grain substrate (rice, wheat); experimental flour mixes of wheat bread and first-grade baking flour with mycelial biomass powder; bread made from the experimental flour mixes. The experimental part included standard methods used in the bakery industry. The mycelial biomass of C. militaris and L. edodes fungi proved to be a promising baking additive because it possessed hydrolytic enzymes and was rich in protein substances (32.2 ± 1.5 and 26.4 ± 2.0%, respectively), specific mushroom polysaccharides (36.7 ± 0.8 and 52.2 ± 1.2%, respectively), and carotenoids (1600 ± 40 mcg/g of C. militaris biomass). The active amylases and proteinases in the mycelial biomass powder improved the sugar-forming ability and reduced the falling number. In addition, they raised the amount of washed gluten with a slight decrease in elasticity, as well as provided an acceptable structure and viscosity of the dough at 1–4% of mycelial biomass powder. This dose resulted in an optimal bread formulation of standard quality. A bigger amount caused the crumb to darken and increased its humidity while reducing the specific volume. The bread samples with C. militaris were too acid. Mycelial biomass of C. militaris and L. edodes proved to be a good source of enzymes to be used with grain substrates in bakery production. Further research is needed to define the optimal dose and processing modes.

Crecimiento micelial y producción de lacasa y peroxidasas por Pleurotus ostreatus y Agrocybe aegerita en fermentación líquida

Mycelial growth of Pleurotus ostreatus and Agrocybe aegerita in malt extract broth was evaluated. Laccase, manganese peroxidase (MnP), lignin peroxidase (LiP) and unspecific peroxygenase (UnP) activities were determined in both strains, using biochemical and polyacrylamide gel electrophoresis techniques. No strain showed MnP, LiP, and UnP activities. P. ostreatus had higher biomass production and laccase yield values than those shown by A. aegerita. P. ostreatus produced approximately twice as much biomass (Xmax) compared to A. aegerita (9.12 and 5.27 g/L, respectively). Maximum laccase activity (Emax) was nine-fold higher in P. ostreatus than in A. aegerita (106.5 and 12.23 U/L, respectively). P. ostreatus and A. aegerita showed 3 bands (estimated to be approximately 42, 55, 85 and 212 kDa) and one band (estimated to be approximately 35.2 kDa) with laccase activity, respectively. These results show that laccases are constitutively produced in both fungal species, whereas MnP, LiP and UnP are inducible enzymes. P. ostreatus has a great potential in the biotechnological production of laccases.

Degradation of Polypropylene Using Fungal Enzyme As A Sustainable Approach To Management Plastic Waste

Polypropylene (PP) is a major environmental problem in Malaysia because it has been ranked the 28th highest plastic polluter in the world (at 56kg per capita per year) in 2021. Landfilling is one of the most common ways of dealing with plastic because leachate may cause increased probability of cancer and neurological impairment in humans. The use of fungi in mycoremediation makes the process eco-friendly. In addition, fungi have a vast hyphal network and broader metabolic competence. The objective of this study was to investigate fungi remediation of PP via the detection of manganese peroxidase and laccase activity in Bushnell Haas Broth (BHB). PP degradation activity was measured via the activity of laccase and manganese peroxidase at a wavelength of 450nm and 610nm, respectively. Of the 17 species of fungi isolated from the Jeram landfill, 12 species of fungi showed growth in BHB with PP as the sole carbon source. Penicillium sp. 1, Aspergillus sp., Penicillium levitum, Talaromyces louisianensis, Aspergillus tamarii, Cunninghamella bertholletiae, Penicillium sp. 2 and Aspergillus niger demonstrated high and longer laccase activity, and these fungi could be considered as potential fungi. P. levitum, P. janthinellum, Penicillium sp, and T. louisianensis have high and longer MnP activity. In summary, P. levitum and T. louisianensis have a high and long duration of MnP and laccase activity in degrading PP, which can be developed and integrated into plastic waste management.

Co-composting of dewatered sludge and wheat straw with newly isolated Xenophilus azovorans: Carbon dynamics, humification, and driving pathways

Composting is a biological reaction caused by microorganisms. Composting efficiency can be adequately increased by adding biochar and/or by inoculating with exogenous microorganisms. In this study, we looked at four methods for dewatered sludge waste (DSW) and wheat straw (WS) aerobic co-composting: T1 (no additive), T2 (5% biochar), T3 (5% of a newly isolated strain, Xenophilus azovorans (XPA)), and T4 (5% of biochar-immobilized XPA (BCI-XPA)). Throughout the course of the 42-day composting period, we looked into the carbon dynamics, humification, microbial community succession, and modifications to the driving pathways. Compared to T1 and T2, the addition of XPA (T3) and BCI-XPA (T4) extended the thermophilic phase of composting without negatively affecting compost maturation. Notably, T4 exhibited a higher seed germination index (132.14%). Different from T1 and T2 treatments, T3 and T4 treatments increased CO2 and CH4 emissions in the composting process, in which the cumulative CO2 emissions increased by 18.61–47.16%, and T3 and T4 treatments also promoted the formation of humic acid. Moreover, T4 treatment with BCI-XPA addition showed relatively higher activities of urease, polyphenol oxidase, and laccase, as well as a higher diversity of microorganisms compared to other processes. The Functional Annotation of Prokaryotic Taxa (FAPROTAX) analysis showed that microorganisms involved in the carbon cycle dominated the entire composting process in all treatments, with chemoheterotrophy and aerobic chemoheterotrophy being the main pathways of organic materials degradation. Moreover, the presence of XPA accelerated the breakdown of organic materials by catabolism of aromatic compounds and intracellular parasite pathways. On the other hand, the xylanolysis pathway was aided in the conversion of organic materials to dissolved organics by the addition of BCI-XPA. These findings indicate that XPA and BCI-XPA have potential as additives to improve the efficiency of dewatered sludge and wheat straw co-composting.

Effects of Fungal Solid-State Fermentation on the Profile of Phenolic Compounds and on the Nutritional Properties of Grape Pomace.

Grape pomace (GP) is considered a natural source of bioactive compounds. To improve the extractability of bioactive compounds, in this work, GP was biologically treated for 15 days with the white-rot fungus Trametes versicolor in laboratory jars and a tray bioreactor under solid-state fermentation (SSF) conditions. During SSF, the activity of lignolytic (laccase and manganese peroxidase) and hydrolytic (xylanase, cellulase, β-glucosidase, and invertase) enzymes was measured, with the activities of laccase (2.66 U/gdb in jars and 0.96 U/gdb in the bioreactor) and xylanase (346.04 U/gdb in jars and 200.65 U/gdb in the bioreactor) being the highest. The effect of the complex enzyme system was reflected in the changes in the chemical composition of GP with increasing ash, crude protein, and free fat content: 28%, 10%, and 17% in the laboratory jars, and 29%, 11%, and 7% in the bioreactor, respectively. In addition, the biological treatment improved the extractability of 13 individual phenolic compounds. Therefore, the applied SSF technique represents an effective strategy to improve the profile of phenolic compounds and the nutritional composition of GP, promoting their valorization and opening the door for potential applications in the food industry and other sectors.

Short Communication: Candida sp. isolated from mangrove soils for biological decolorization of textile reactive dyes

Abstract. Boontanom P, Chantarasiri A. 2024. Short communication: Candida sp. isolated from mangrove soils for biological decolorization of textile reactive dyes. Biodiversitas 25: 2595-2602. Effluent discharge from dye-related industries is a significant environmental pollution problem and a concern for human health. Dyes have harmful effects on aquatic organisms due to their toxic properties. One possible solution is using microorganisms for the biological decolorization of textile reactive dyes as an eco-friendly and potentially lucrative alternative to physicochemical processes. Therefore, this study isolated an effective dye-decolorizing yeast from mangrove soil samples in Thailand and investigated the decolorization efficiency of eight textile reactive dyes under experimental conditions. Yeasts have several advantages over other bacteria and fungi for the biological decolorization of textile reactive dyes, but the number of dye-decolorizing yeasts discovered in mangrove soils remains scarce. The most effective dye-decolorizing yeast, isolate RY21703, showed Remazol Brilliant Blue R (RBBR) decolorization of 37.50±0.07% within 72 h of incubation. This yeast isolate was genetically and phylogenetically identified as Candida sp. strain RY21703 and produced 0.97±0.08 U/mL of crude laccase activity, an essential enzyme in dye decolorization mechanisms. Candida sp. strain RY21703 showed strong decolorization efficiency after 72 h of incubation in all azo-reactive dyes, ranging from 27.32±3.34% (CI Reactive Orange 122) to 61.45±1.43% (CI Reactive Green 19). This strain also decolorized phthalocyanine reactive dye (CI Reactive Blue 21) by 60.71%. Findings suggested that this mangrove yeast can be used for the biological decolorization of dyeing wastewater.

A Novel Bio-Adhesive Based on Chitosan-Polydopamine-Xanthan Gum for Glass, Cardboard and Textile Commodities.

The escalating environmental concerns associated with petroleum-based adhesives have spurred an urgent need for sustainable alternatives. Chitosan, a natural polysaccharide, is a promising candidate; however, its limited water resistance hinders broader application. The aim of this study is to develop a new chitosan-based adhesive with improved properties. The polydopamine association with chitosan presents a significant increase in adhesiveness compared to pure chitosan. Polydopamine is synthesized by the enzymatic action of laccase from Trametes versicolor at pH = 4.5, in the absence or presence of chitosan. This pH facilitates chitosan's solubility and the occurrence of catechol in its reduced form (pH < 5.5), thereby increasing the final adhesive properties. To further enhance the adhesive properties, various crosslinking agents were tested. A multi-technique approach was used for the characterization of formulations. The formulation based on 3% chitosan, 50% polydopamine, and 3% xanthan gum showed a spectacular increase in adhesive properties when tested on glass, cardboard and textile. This formulation increased water resistance, maintaining the adhesion of a sample soaked in water for up to 10 h. For cardboard and textile, material rapture occurred, in mechanical tests, prior to adhesive bond failure. Furthermore, all the samples showed antiflame properties, expanding the benefits of their use. Comparison with commercial glues confirms the remarkable adhesive properties of the new formulation.

Biofoams with untapped enzymatic potential produced from beer bagasse by indigenous fungal strains

White rot fungi are promising organisms for the production of mycelial-based biofoams, providing a sustainable means of valorizing lignocellulosic wastes. This study explores the utilization of two indigenous fungal species, isolated from Argentina and belonging to the genera Trametes, for producing biofoams from brewery waste. The resulting biofoams exhibited an average density of 0.30 g cm−3, a Young’s modulus of approximately 1 MPa, and a compressive stress of around 19 MPa. Additionally, the variation of laccase activity throughout the biofoam production process was evaluated. Surprisingly, residual laccase activity was detected in the biofoams following oven drying at temperatures of 60, 80, and 100 °C. This detection highlights the untapped enzymatic potential of the biofoams and positions them as promising green catalysts for various biotechnological applications.

Improved productivity and dye removal performance of Trametes versicolor pellets using rice husk as a co-substrate

Pellet production represents a critical step for several processes requiring fungal biomass, nevertheless, its optimization is seldom reported. The use of finely ground rice husk as a microcarrier and co-substrate permitted a marked increase (≈ 2.7×) in the productivity of fungal pellet production using Trametes versicolor compared to traditional production methods. The pellets show similar structure and smaller size compared to typical sole-mycelium pellets, as well as comparable laccase activity. The efficiency of the pellets for biodegradation was confirmed by the removal of the crystal violet dye, achieving significantly faster decolorization rates compared to the traditionally produced pellets. The use of these pellets during the continuous treatment of the dye in a stirred tank bioreactor resulted in 97% decolorization operating at a hydraulic residence time of 4.5 d.

Fabrication of superior laccase-mimicking enzyme with catalytic oxidative and photothermal properties for anti-bacterial and dual-mode glutathione S-transferase monitoring

A novel laccase mimic enzyme Cu–Mn with excellent photothermal properties was firstly prepared via a combination of hydrothermal and in situ synthesis. Cu–Mn nanozymes could catalyze the typical laccase substrate 2,4-dichlorophenol (2,4-DP) to generate the red quinone imine. Further, loading the MnO2 nanosheets with photothermal properties, Cu–Mn nanozymes possessed not only excellent laccase catalytic activity, but also high photothermal conversion efficiency. The presence of glutathione S-transferase (GST) recovered the glutathione (GSH)-induced weakness of the laccase activity and photothermal properties of Cu–Mn. Hence, a GST enzyme-regulated dual-mode sensing strategy was established based on Cu–Mn nanozymes. The detection limits of GST monitoring based on colorimetric and photothermal methods were 0.092 and 0.087 U/L with response times of 20 min and 8 min, respectively. Furthermore, the proposed method enabled the measuring of GST levels in human serum and was successfully employed in the primary evaluation of hepatitis patients. Another attraction, the impressive photothermal behavior also endowed the Cu–Mn nanozymes with promising antimicrobial properties, which exhibited significant antimicrobial effects against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus). Unsurprisingly, multifunctional Cu–Mn nanozymes certainly explore new paths in biochemical analysis and antimicrobial applications.

Cobalt catalyzed carbonyl functionalization to boost the biodegradation of polyethylene by Bacillus velezensis C5

Polyethylene plastics are widely used in daily life since known for their resistance to biodegradation, but posing a significant environmental challenge. The biodegradation of polyethylene can contribute to environmental protection and facilitate energy conservation, in comparison with physical or chemical methodologies. However, the stable and inert C–C bond structure of polyethylene limits biodegradation effectiveness, leading to a slow breakdown rate and extended life cycle. In this study, Co(acac)2 was used as a catalyst to generate free radicals that activated the interface of low-density polyethylene, resulting in the formation of oxygen-containing functional groups. Under the condition of Co(acac)2-mediated catalysis at 120 °C for 24 h, the carbonyl index of polyethylene rose from 0 to 2.99. The weight-average molecular weight of polyethylene was reduced by 8.77 % compared to the control, leading to the generation of small molecules. The density functional theory elucidated showed that the active oxygen substitution in the single electron transfer reaction was driven by the high-energy intermediate alkyl radical. The bond energy of the resulting carbonyl functional group (CO) is 76.4 % lower than that of the original C–C bond, making it more susceptible to cleavage and depolymerization. Following 90 d of biodegradation, the laccase activity showed a 25 % increase compared to the control, indicating an improved oxidase release by chemical oxidation. The weight loss of low-density polyethylene was 23.91 %, and the microbial degradation efficiency was 2.32 times higher. This strategy significantly improves the ability of microorganisms to degrade low-density polyethylene and is a novel approach to the design of pathways for the polyolefin degradation.

Phenotypic characteristics of the mycelium of Pleurotus geesteranus using image recognition technology.

Phenotypic analysis has significant potential for aiding breeding efforts. However, there is a notable lack of studies utilizing phenotypic analysis in the field of edible fungi. Pleurotus geesteranus is a lucrative edible fungus with significant market demand and substantial industrial output, and early-stage phenotypic analysis of Pleurotus geesteranus is imperative during its breeding process. This study utilizes image recognition technology to investigate the phenotypic features of the mycelium of P. geesteranus. We aim to establish the relations between these phenotypic characteristics and mycelial quality. Four groups of mycelia, namely, the non-degraded and degraded mycelium and the 5th and 14th subcultures, are used as image sources. Two categories of phenotypic metrics, outline and texture, are quantitatively calculated and analyzed. In the outline features of the mycelium, five indexes, namely, mycelial perimeter, radius, area, growth rate, and change speed, are proposed to demonstrate mycelial growth. In the texture features of the mycelium, five indexes, namely, mycelial coverage, roundness, groove depth, density, and density change, are studied to analyze the phenotypic characteristics of the mycelium. Moreover, we also compared the cellulase and laccase activities of the mycelium and found that cellulase level was consistent with the phenotypic indices of the mycelium, which further verified the accuracy of digital image processing technology in analyzing the phenotypic characteristics of the mycelium. The results indicate that there are significant differences in these 10 phenotypic characteristic indices ( ), elucidating a close relationship between phenotypic characteristics and mycelial quality. This conclusion facilitates rapid and accurate strain selection in the early breeding stage of P. geesteranus.

Carbon fixation mechanism of fungal community bypass strategy in rice straw composting combined with functional microbes: inhibition from cellobiose to glucose pathway

Composting offers an eco-friendly approach, converting organic solid waste into valuable soil enhancer products. Three experimental treatments were designed to explore the microbial mechanisms influencing lignocellulose loss in rice straw composting: CK (the control), B4 (inoculated with Bacillus subtilis), and Z1 (inoculated with Aspergillus fumigatus). The results showed significant increases in carboxymethyl cellulase, cellobiohydrolase, laccase, and xylanase activities during B4 and Z1composting. However, lignin peroxidase and manganese peroxidase were not significantly affected, and β-glucosidase was inhibited. Additionally, microbial inoculation stimulated lignin loss, with B4 and Z1 composting increasing degradation by 14.42% and 16.29%, respectively, compared to the CK. Simultaneously, humic substance content increased as microbial inoculation inhibited β-glucosidase, causing cellobiose to accumulate and divert into a pathway that forms humic substances. The random forest model showed that Symmetrospora and Phaeosphaeria significantly boosted lignocellulose loss in B4 and Z1 composting by promoting fungi functional aggregation, thus accelerating the degradation and transformation process. This study explored the microbial mechanism of lignocellulose loss and provided new insights into lignocellulose conversion and carbon fixation.

Biodegradation of Malachite Green Dye by Novel Isolated Bacillus Species AAV from Garden Soil

Malachite green (MG) dye commonly use in textile and paper printing industry to a great extent. Textile effluent released from industries including dyes must be treated before release into the environment due to its toxic nature. In present study, newly isolated bacterial species was able to decolorize MG dye (100%) in 1 h at shaking condition and 94% at static condition. 16S rRNA analysis revealed an isolate as Bacillus sp. AAV. Lignin peroxidase, laccase and tyrosinase enzymes from Bacillus sp. AAV showed significant increased activity during decolourisation. There was 138, 369 and 164% trek in activity of LiP, laccase and tyrosinase after MG decolourization, respectively. Bacillus sp. AAV could decolourise MG efficiently at alkaline pH (8-10) and at 40°C temperature. Biodegradation was monitored by UV-VIS spectrophotometer. Gas chromatography-Mass spectroscopy data was used to propose the degradation pathway of MG dye. The newly isolated Bacillus sp. AAV was able to decolourise ten various types of dyes and textile dye effluent. Phytotoxicity test by using seeds of wheat and sorghum was also carried out to check toxicity of MG dye metabolites. The study reveals that there was no toxicity with respect to tested seeds. This study suggests that Bacillus sp. AAV could be a useful microorganism or its enzyme system for textile dyes and effluent treatment.

Enhancing quality of ruminant feed through fungal treatment: Usage of bamboo shoot residues.

In this investigation, we explore the harnessing of bamboo shoot residues (BSR) as a viable source for ruminant feed through fungal treatment, with the overarching objective of elevating feed quality and optimizing bamboo shoot utilization. The white-rot fungi (Wr.fungi), Aspergillus niger (A.niger), and its co-cultures (A.niger&Wr.fungi) were employed to ferment BSR. And the impact of different fermentation methods and culture time on the chemical composition (Crude protein Ash, neutral detergent fibre and acid detergent fibers), enzyme activity (Cellulase, Laccase, Filter paperase and Lignin peroxidase activities), and rumen digestibility in vitro were assessed. The findings reveal a nota ble 30.39% increase in crude protein in fermented BSR, accompanied by respective decreases of 13.02% and 17.31% in acid detergent fiber and neutral detergent fibre content. Enzyme activities experienced augmentation post-fermentation with A.niger&Wr.fungi. Specifically, the peak Cellulase, Laccase, and Lignin peroxidase activities for BSR with Wr.fungi treatment reached 748.4 U/g, 156.92 U/g, and 291.61 U/g, respectively, on the sixth day of fermentation. Concurrently, NH3-N concentration exhibited an upward trend with prolonged fermentation time. Total volatile fatty acids registered a decline, and the Acetate/Propionate ratio reached its nadir after 6 days of fermentation under the A.niger&Wr.fungi treatment. These outcomes furnish a theoretical foundation for the development of ruminant feeds treated via fungal co-culture.

Hydrothermal liquefaction aqueous phase mycoremediation to increase inorganic nitrogen availability

Hydrothermal liquefaction aqueous phase (HTL-AP) is a waste product from a thermochemical process where wet biomass is converted into biocrude oil. This nutrient-rich wastewater may be repurposed to benefit society by assisting crop growth after adequate treatment to increase inorganic nitrogen, especially NO3−. This study aims to increase HTL-AP inorganic nitrogen, specifically NH3/NH4+ and NO3−, through fungal remediation for further use in hydroponic systems. Trametes versicolor, a white-rot fungus known for degrading a range of organic pollutants, was used to treat a diluted (5 %) HTL-AP for 9 days. No fungal growth was observed, but T. versicolor activity was suspected by laccase activity throughout cultivation time. NO3−-N and NH3/NH4+-N increased by 17 and 8 times after three days of fungal treatment, which was chosen as the appropriate time for HTL-AP fungal treatment as it resulted in the highest concentration of NO3−-N. The addition of nitrifying bacteria to the fungal treatment resulted in a twofold increase in NO3−-N concentration compared to the fungal treatment alone, indicating an enhancement in treatment efficacy. COD decreased by 51.33 % after 24 h, which may be related to the fungus’ capacity to reduce the concentration of organics in the wastewater; nonetheless, COD increased in the following days, which may be related to the release of fungal byproducts. T. versicolor shows promise as a potential candidate for increasing inorganic nitrogen in HTL-AP. However, future studies should primarily address HTL-AP toxicity, reducing NH3/NH4+-N while increasing NO3−-N, and hydroponics crop production after fungal treatment.

Improved expression of Cerrena unicolor Laccase in Aspergillus niger via combined strategies and its applications

The application of laccases in biotechnology and industry is an expanding research field. Laccases derived from Cerrena unicolor (C. unicolor) exhibit notable potential in the food and industrial sectors. However, generating sufficient yields of this laccase through heterologous expression to meet commercial demands remains a challenge. Therefore, we heterologously expressed LACCASE2 (Lac2), a laccase gene from C. unicolor, in Aspergillus niger. By incorporating strategies such as codon optimization, molecular chaperone-assisted expression, and atmospheric and room-temperature plasma (ARTP) mutagenesis, we successfully screened the strain OPT-HacA-M10 with the highest laccase yield, which exhibited a remarkable enzymatic activity of 416.8 U/mL in a 50-L fermenter. We further assessed the enzymatic properties of the recombinant laccase rLac2, focusing on its capabilities in dye decolorization and mycotoxin degradation. In the absence of a mediator, rLac2 exhibited extremely high degradation efficiency for Remazol Brilliant Blue R and indigo. Impressively, outstanding results were achieved with this laccase in denim bleaching. In mycotoxin degradation tests, with methyl syringate as a mediator, rLac2 achieved degradation rates of over 94% for aflatoxin B1 and zearalenone. In summary, due to its heightened laccase activity and versatile applications, our enhanced strain is highly suitable for industrial and food sectors.

Effects of Orange Peel Extract on Laccase Activity and Gene Expression in Trametes versicolor.

The genome of Trametes versicolor encodes multiple laccase isozymes, the expression of which is responsive to various conditions. Here, we set out to investigate the potential of orange peel extract as an inducer of laccase production in this white-rot fungus, in comparison to the previously identified inducing chemical compound, veratryl alcohol. For four geographically distinct T. versicolor strains, a positive correlation has been observed between their oxidative activity and incubation time in liquid cultures. The addition of 20% orange peel extract or 5 mM veratryl alcohol caused a rapid increase in the oxidative potential of T. versicolor M99 after 24 h, with a more pronounced effect observed for the orange peel extract. To elucidate the underlying molecular mechanisms of the induced laccase activity, a transcriptional gene expression analysis was performed for the seven individual laccase genes in T. versicolor, revealing the upregulation of several laccase genes in response to the addition of each inducer. Notably, the gene encoding TvLac5 demonstrated a substantial upregulation in response to the addition of 20% orange peel extract, likely contributing to the observed increase in its oxidative potential. In conclusion, our results demonstrate that orange peels are a promising agro-industrial side stream for implementation as inducing agents in large-scale laccase production with T. versicolor.

Effect of substrate moisture content during cultivation of Hericium erinaceus and subsequent vermicomposting of spent mushroom substrate in a continuous feeding system

Cultivation of Hericium erinaceus depends on various factors, one of which is water content in the substrate. This parameter influences not only the growth rate of the mushroom but also enzymatic activity, which is important for substrate decomposition and for the later usage of spent mushroom substrate (SMS). This study compared parameters, such as mycelial growth, pH and enzymatic activity in substrates with different initial water content. During cultivation, the water content and pH decreased in all variants, but the activity of hydrolytic enzymes increased with time and was higher in variants with higher water content (70% and 75%); however, the activity of ligninolytic enzymes decreased during cultivation. The production of 1 kg of mushrooms generates about 5 kg of SMS. Vermicomposting is a natural method for processing SMS, as it involves a combination of earthworms, microorganisms and enzymatic activity; thus, we compared the differences between variants with and without earthworms using continuous feeding vermicomposters. The C:N ratio in the variant with earthworms radically decreased from 153.7:1 to 16.5:1. The ratio of bacteria to fungi in both variants was highest in the oldest compost layer in the vermicomposters. The variant without earthworms exhibited the highest enzymatic activity of β-D-glucosidase and Mn-peroxidase, but the highest activity of cellobiohydrolase and laccase occurred in the variant with earthworms. The vermicomposting process is ideal for this type of biowaste, as it produces a fertilizer rich in beneficial microorganisms and enzymatic activity.