Lac Activity Research Articles

Insight into the role of antioxidant in microbial lignin degradation: Ascorbic acid as a fortifier of lignin-degrading enzymes

BackgroundMicrobial-driven lignin depolymerization has emerged as a promising approach for lignin degradation. However, this process is hindered by the limited activity of lignin-degrading enzymes. Antioxidants are crucial for maintaining redox homeostasis in living cells, which can impact the efficiency of enzymes. Ascorbic acid (AA) is well-known for its antioxidant properties, while Trametes versicolor is a commonly used lignin-degrading fungus capable of secreting laccase (Lac) and manganese peroxidase (MnP). Thus, AA was selected as model antioxidant and added into the culture medium of T. versicolor to examine the effect of antioxidants on the activity of lignin-degrading enzymes in the fungus.ResultsThe presence of AA resulted in a 4.9-fold increase in the Lac activity and a 3.9-fold increase in the MnP activity, reaching 10736 U/L and 8659 U/L, respectively. This increase in enzyme activity contributed to a higher lignin degradation rate from 17.5% to 35.2%, consistent with observed morphological changes in the lignin structure. Furthermore, the addition of AA led to a reduction in the molecular weights of lignin and an increase in the content of degradation products with lower molecular weight, indicating more thorough degradation of lignin. Proteomics analysis suggested that the enhancement in enzyme activity was more likely to attributed to the reinforcement of AA on oxidative protein folding and transportation, rather than changes in enzyme expression.ConclusionsThe addition of AA enhanced the performance of enzymes responsible for lignin degradation in terms of enzyme activity, degradation rate, lignin structural change, and product mapping. This study offers a feasible strategy for enhancing the activity of lignin-degrading enzymes in the fungus and provides insights into the role of antioxidant in microbial lignin degradation.

Trametes cingulata: A white rot fungus in decolorization of azo dye reactive red 239

AbstractBackgroundAzo dyes in textile effluents represent a particular health concern because they include azo groups (NN), which are reactive with DNA nucleic acids. The enzymes produced by white rot fungi can biodegrade a broad range of environmental contaminants. This work addresses this by concentrating on novel and effective optimal conditions for Trametes cingulata to produce oxidative enzymes and the capacity to decolorize the azo dye reactive red 239.ResultsA multifactorial experimental design optimized enzymatic activity and azo dye decolorization. Concentrations of 2.5 g L−1 of copper sulfate (CS) and 3.0 g L−1 of yeast extract (YS) for 16 days produced 100% decolorization, with 7.72 U mL−1 of laccase (Lac) and 0.013 U mL−1 of lignin peroxidase (Lip). These were found to be the ideal conditions for the decolorization process. The maximal Lac activity was 12.22 U mL−1 with 2.5 g L−1 CS, 25.0 g L−1 YS and 16 days, in addition to 0.14 U mL−1 Lip activity and 59% decolorization. It was possible to ascertain that the dye's functional groups had been adsorbed to the fungal mycelium by employing Fourier transform infrared spectroscopy. Images obtained from scanning electron microscopy analyses enable the distinction of certain features that signify the adsorption process. Additionally, under ideal decolorization conditions, a 55% chemical oxygen demand decrease was noted.ConclusionThe findings reported show that T. cingulata may decolorize effluents containing azo dyes using two distinct processes: fungal mycelium biosorption and enzymatic degradation. © 2025 Society of Chemical Industry (SCI).

Potential of Indonesian cocoa pod husk for production of ligninolytic enzymes laccase and manganese peroxidase from Trametes hirsuta

Lignocellulosic biomass waste is a great potential source of cellulose and cellulose derivative bioproducts. Biomass pretreatment which involves ligninolytic enzymes is an environmentally friendly process that minimizes the use of harsh chemicals and energy input. This study evaluated white rot fungi and inducers (corncob, pineapple leaf, sorghum, and cocoa pod husk) to produce laccase (Lac) and manganese peroxidase (MnP). Enzyme production was optimized by using Plackett Burman and response surface methodology. Purification was undertaken by ammonium sulfate precipitation, dialysis, and anion exchange chromatography. Trametes hirsuta and cocoa pod husk as producer and inducer, respectively, resulted in the highest enzyme activities. The activities of Lac and MnP were optimum at 762.25 U/L and 596.92 U/L, respectively. The optimum pH and temperature for Lac and MnP were pH 3 (room temperature) and 60 °C (pH 5). The expected Lac and MnP were observed at ~65 kDa and 35–50 kDa protein band, respectively.

Enhanced degradation of phototreated recycled and unused low-density polyethylene films by Pleurotus ostreatus.

Polyethylene, one of the most used petroleum-derived polymers, causes serious environmental pollution. The ability of Pleurotus ostreatus to degrade UV-treated and untreated recycled and unused (new) low-density polyethylene (LDPE) films was studied. We determined the fungal biomass production, enzyme production, and enzyme yield. Changes in the chemical structure and surface morphology of the LDPE after fungal growth were analyzed using FTIR spectroscopy and SEM. Functional group indices and contact angles were also evaluated. In general, the highest Lac (6013 U/L), LiP (2432 U/L), MnP (995 U/L) and UP (6671 U/L) activities were observed in irradiated recycled LDPE (IrRPE). The contact angle of all samples was negatively correlated with fermentation time; the smaller the contact angle, the longer the fermentation time, indicating effective biodegradation. The IrRPE samples exhibited the smallest contact angle (49°) at 4 weeks, and the samples were fragmented (into two pieces) at 5 weeks. This fungus could degrade unused (new) LDPE significantly within 6 weeks. The biodegradation of LDPE proceeded faster in recycled than in unused samples, which can be enhanced by exposing LDPE to UV radiation. Enzymatic production during fungal growth suggest that LDPE degradation is initiated by laccase (Lac) followed by lignin peroxidase (LiP), whereas manganese peroxidase (MnP) and unspecific peroxygenase (UP) are involved in the final degradation process. This is the first experimental study on the fungal growth and its main enzymes involved in LDPE biodegradation. This fungus has great promise as a safe, efficient, and environmentally friendly organism capable of degrading LDPE.

PtCo with oxidase-like activity and laccase for synergistic catalytic degradation of phthalic acid esters

Phthalic acid esters (PAEs) as common plasticizers, providing convenience to humans. However, they also present a potential threat to ecosystems and human health as emerging contaminants. In this study, co-immobilization of nanozyme (PtCo) and laccase (Lac) into dendritic mesoporous silica (DMSN) constitutes nanomaterials (Lac@PtCo@DMSN). PtCo with an atomic ratio of 3:1 has the highest oxidizing activity. DMSN exhibited a maximum Lac loading capacity of 365 mg/g and activity of Lac@PtCo@DMSN exhibits excellent pH, temperature, and storage stability and reusability, and demonstrated greater recoverability. Remarkably, Lac@PtCo@DMSN (50 mg) achieved 81.83% degradation of total PAEs within 72 h and maintained 72.44% degradation of dimethyl phthalate (DMP) in the fifth cycle. Electron transfer between Pt, Co and adsorbed oxygen (O2ads) in PtCo can generate •OH and •O2−, which were the dominant reactants for PAEs degradation. •OH could degrade PAEs to phthalic acid via H-abstration and •OH addition. •OH effectively enhanced Lac activity, and promoted the synergistic catalytic performance of nanozymes and natural enzymes. The degradation of phthalic acid by Lac accelerated the release of PtCo@DMSN reaction sites, resulting in significantly enhanced PAEs degradation. Thus, artificial/natural enzymes can degrade PAEs without exogenous additives to solve the limitation of Lac application, providing a new strategy for degrading contaminants in water.

Pretreatment and saccharification of corn cobs using partially purified fungal ligninozymes

AbstractCorn cobs consist primarily of a lignocellulosic material comprising hemicellulose, cellulose, and lignin in a crystalline state, which is resistant to microbial saccharification. Bioethanol production from corn cobs has rarely been attempted, especially using chemical pretreatment methods.The present study deals with the production and purification of fungal (Phanerochaete chrysosporium MTCC 787 and Pleurotus florida PAU 22‐01) extracellular ligninolytic enzymes – lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lac) – followed by their utilization for the biological pretreatment of corn cobs along with saccharification using commercial cellulase. Crude LiP, MnP, and Lac demonstrated specific activity of 2.23, 2.1, and 2.63 U/mg, respectively.The one‐step purification of crude enzyme using diethyl amino ethyl (DEAE) cellulose ion exchange chromatography resulted in 11.3, 10.1 and 8.62‐fold purification of LiP, MnP and Lac activity, respectively, with corresponding specific activity of 25.1 U/mg (LiP), 21.2 U/mg (MnP) and 22.7 U/mg (Lac) in the partially purified ligninozymes. Using the latter, biological pretreatment of 2.5 g corn cobs in a reaction volume of 30 mL containing approximately 200 units of Lac, Lip and MnP enzymes (in phosphate buffer, pH 6) resulted in a maximum of 78.4% delignification with a saccharification efficiency of 97.1% using commercial cellulases.

Producción de oxidasas por Trametes versicolor crecido sobre residuos verdes y sobre espuma de poliuretano en fermentación en estado sólido: Un estudio comparativo

Green waste (GW) is generated by the maintenance of public or private green spaces. It is necessary to find ecological alternatives for GW utilization, aiming to avoid accumulation of this material at the environment. In this research, the production of laccase (Lac), lignin peroxidase (LiP), manganese peroxidase (MnP) and unspecific peroxygenase (UnP) produced by Trametes versicolor grown on GW as a substrate and on polyurethane foam (PUF) as an inert support in solid state fermentation was evaluated. T. versicolor showed higher values of Lac, MnP, UnP and LiP activities (34, 943, 1023 and 766 U/gS, respectively) when grown on GW than when grown on PUF (10.9, 588, 559 and 229 U/gS, respectively). These results suggest that T. versicolor produced Lac inducible and constitutively, while LiP, MnP and UnP were induced by GW at the beginning of fungal growth, however, these enzymes were constitutive and inducible during the rest of the fermentation. The production of oxidases and peroxidases was induced and increased by GW. It is suggested that LiP is involved (as a constitutive enzyme) at the beginning of the exponential phase, while MnP and UnP participate in fungal growth at the end of fermentation. To our knowledge, this is the first detailed study on the main lignincellulose-degrading fungal enzymes involved in GW degradation by fungi. In particular, the relevance of UnP was showed as peroxidase involved in lignocellulosic substrates biodegradation.

Caatinga, Amazon and Atlantic Forest as natural sources for microbial lignocellulolytic enzymes.

Brazilian biomes are important sources for environmental microorganisms, including efficient metabolic machineries, like actinomycetes. These bacteria are known for their abilities to produce many bioactive compounds, including enzymes with multiple industrial applications. The present work aimed to evaluate lignocellulolytic abilities of actinomycetes isolated from soil and rhizosphere samples collected at Caatinga, Atlantic and Amazon Forest. Laccase (Lac), lignin peroxidase (LiP), manganese peroxidase (MnP) and cellulase were evaluated for their efficiency. These enzymes have an essential role in lignin decomposition, through oxidation of phenolic and non-phenolic compounds, as well as enzymatic hydrolysis of vegetal biomass. In this sense, a total of 173 actinomycetes were investigated. Eleven (11) of them were selected by their enzymatic performance. The actinomycete AC166 displayed some activity in all analysed scenarios in terms of Lac, MnP and LiP activity, while AC171 was selected as the most promising strain, showing the following activities: 29.7 U.L-1 for Lac; 2.5 U.L-1 for LiP and 23 U.L-1 for MnP. Cellulolytic activities were evaluated at two pH conditions, 4.8 and 7.4, obtaining the following results: 25 U.L-1 and 71 U.L-1, respectively. Thermostability (4, 30 and 60 o C) and salinity concentrations (0 to 4M) and pH variation (2.0 to 9.0) stabilities of the obtained LiP and Lac enzymatic extracts were also verified. The actinomycete strain AC171 displayed an adaptable response in distinct pH and salt profiles, indicating that bacterial LiP was some halophilic type. Additionally, the strain AC149 produced an alkali and extreme halophilic lignin peroxidase, which are promising profiles for their future application under lignocellulosic biomass at bioethanol biorefineries.

Efficient crop straws biotreatment using the fungus Cerrena Unicolor GC.u01

Lignin is main composition of agricultural biomass which can be decomposed through enzymatic hydrolysis by fungi. However, there are still needs to identify more efficient and effective fungal stain for biomass valorization. In this study, lignin degrading fungi from birch forest were screened for sustainable degradation of waste agricultural straws. The most effective strain was identified as Cerrena unicolor GC.u01 using 18 S rDNA gene-sequencing technology. Three different crop straws (corn stalk, rice and wheat straws) were used for the biotreatment studies. The activities of lignin degrading enzymes, laccase (Lac), cellulase and xylanase, secreted by C. unicolor were also determined. Scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analyzer (TGA) were further used to monitor the effects of the biotreatment process. The results showed that C. unicolor degraded 34.3% rice straw lignin, a percentage which was higher than other isolated strains after 15 d straw liquid fermentation. The highest Lac activity (8.396 U•mL− 1) was observed with corn stalk on the 7 d. Cellulase and xylanase activities, in the same biomass, were higher than those of wheat and rice straws after 15 d. Furthermore, SEM, FTIR and TGA analyses showed that C. unicolor pretreatment process had significant effects on corn stalk, rice and wheat straws’ structures. The newly isolated stain of C. unicolor demonstrated high lignin degradation potential that can provide effective, ecofriendly means of valorizing biomass to industrial useable raw-material.

Enhanced biodegradation of toxic pollutants from paper industry wastewater using Pseudomonas sp. immobilized in composite biocarriers and its toxicity evaluation

The present study focused on the immobilization of Pseudomonas putida strain using polyvinyl alcohol mixed with sodium alginate (PVA-SA) and agar-agar (PVA-AA) for the treatment of paper industry wastewater. The bacterial culture immobilized in PVA-SA polymer efficiently removed BOD5, COD, TKN, and TOC, phenol, lignin and color was 69.6 %, 78.6 %, 81.7 %, and 88.0 %, 98.4 %, 65.6 % and 85.7 %, respectively, with 24.8 IU/mL of Lac activity at 6 days of degradation. While using PVA-AA immobilized bacterium the reduction in pollutants; 61.0 %, BOD5; 75.9 %, COD; 76.5 %, TKN; 86.0 %, TOC; 97.9 %, phenol; 62.3 %, lignin and 89.8 %, color respectively with 18.5 IU/mL Lac activity was observed. The content of heavy metals after treatment with immobilized bacterium was also reduced significantly. FTIR analysis of wastewater samples showed that bacterial culture may degrade toxic aromatic compounds significantly. The toxicity data demonstrated that the paper industry wastewater was phytotoxic and cytotoxic in nature, but after treatment, it was reduced significantly.

Ability of marine-derived fungi isolated from polluted saline environment for enzymatic hydrocarbon remediation.

Marine-derived fungi have attracted much attention due to their ability to present a new biosynthetic diversity. About 50 fungal isolates were obtained from Tunisian Mediterranean seawater and then screened for the presence of lignin-peroxidase (LiP), manganese-dependent peroxidase (MnP), and laccase (Lac) activities. The results obtained from both qualitative and quantitative assays showed that four of marine fungi isolates had a high potential to produce lignin-degrading enzymes. They were characterized taxonomically by a molecular method, based on international spacer (ITS) rDNA sequence analysis, as Chaetomium jodhpurense (MH667651.1), Chaetomium maderasense (MH665977.1), Paraconiothyrium variabile (MH667653.1), and Phoma betae (MH667655.1) which have been reported as producers of ligninolytic enzyme in the literature.The enzymatic activities and culture conditions were optimized using a Fractional Factorial design (2 7- 4). Then, fungal strains were incubated with the addition of 1% of crude oil in 50% of seawater for 25days to evaluate their abilities to simultaneously degrade hydrocarbon compounds and to produce ligninolytic enzymes. The strain P. variabile exhibited the highest crude oil degradation rate (48.3%). Significant production of ligninolytic enzymes was recorded during the degradation process, which reached 2730 U/L for the MnP, 410 U/L for LiP, and 168.5 U/L for Lac. The FTIR and GC-MS analysis confirmed that the isolates rapidly biodegrade crude oil under ecological and economic conditions.

Exploring the effect of surfactants on the interaction between laccase and bisphenol A by molecular docking, molecular dynamics, and energy calculations

Bisphenol A (BPA), an endocrine disruptor, has potential threat to human health due to its widespread use as a plasticizer in many industrial products. Laccase (Lac) can degrade BPA well and the intervention of some surfactants can further improve the degradation of BPA by Lac, but the exact details are not known. In this paper, focused on the Lac and BPA, as well as the surfactants rhamnolipid (RL) and polyethylene glycol (PEG) as research objects, we construct nine research systems by molecular docking, and study the effect of these two surfactants on the interaction of Lac-BPA at the molecular level through molecular dynamics (MD) simulation and MM-PBSA prediction. The results showed that these two surfactants aggregated and encapsulated the enzyme in different degrees during the MD simulations, which separated the surface part of the enzyme from the solvent, thereby weakening the environmental influence on Lac activity and changing the local residues conformation of Lac, leading to the reduction of polar solvation free energy and changing the binding state of Lac-BPA. RL promotes the binding of Lac-BPA primarily by influencing the free energy of polar solvents, while PEG weakens the binding free energy of Lac-BPA complex. These results explain the reason for the lower degradation rate of BPA with the addition of PEG than with the addition of RL in the same system under the appropriate conditions. Our work elucidates the mechanism of action by which two surfactants RL and PEG affect the Lac-BPA interaction which will provide a strong basis for improving the degradation of BPA by Lac at the molecular level.

Characterization of Thermostable Lignolytic Enzymes from Penicillium italicum during Biomineralization of Polyethylene

Penicillium italicum isolated from a local dumpsite in Ilara- mokin, Ondo state, Nigeria was used to bio-transform low-density polyethylene (LDPE). Biodegradation was carried out using surface-sterilized and autoclaved LDPE over 3 months experimental period. Bio-remediation was evaluated by determining the weight loss, and physical structure changes which were revealed by scanning electron microscopy. The result showed P. italicum was able to degrade autoclaved LD-PE (25%) more efficiently than surface-sterilized LD-PE (12%). Screening and characterization of lignolytic enzymes (manganese peroxidase (MnP) and laccase (Lac)) produced by P. italicum were also investigated using autoclaved LDPE as a carbon source over 3 months degradation period. The result showed that P. italicum produced optimum MnP and Lac activities in the 6th week of cultivation (90 U/mL and 100 U/mL respectively). Study of their physicochemical properties showed that MnP and Lac had optimum activities (100%) at pH 7.0 and pH 5.0 and were stable at the same pH with 74% residual activities each respectively. The enzymes also had optimum activity (100%) at 70oC and were stable over a wide temperature range (40oC–80oC) with 78% residual activities each after 120 min of incubation. These results show the ability of P. italicum to produce thermostable lignolytic enzymes with the potentials to bio-mineralize recalcitrant plastic polymers such as LDPE.

Evaluation of fungal consortium lignozyme for biodelignification of agricultural residues

AbstractTwo fungal cultures Pleurotus ostreatus (PAU03) and Phanerochaete chrysosporium (MTCC 787) were investigated for their ability to produce ligninolytic enzymes – mainly laccase (Lacc), manganese peroxidase (MnP) and lignin peroxidase (LiP) – under solid‐state fermentation (SSF) conditions, using corn stover as a substrate. Crude LiP, MnP, and Lacc demonstrated specific activity of 11.65 U/mg, 14.9 U/mg and 9.84 U/mg, respectively. The precipitation of crude extract by 70% acetone and subsequent Diethyl amino ethyl (DEAE)‐cellulose ion exchange chromatography resulted in 2.24, 1.23 and 2.60‐fold purification of LiP, MnP and Lac activities, respectively with corresponding specific activities of 26.14 U/mg (LiP), 18.33 U/mg (MnP) and 25.67 U/mg (Lacc) in the partially purified ligninozymes. The latter showed three distinct bands of 40–56 kDA when resolved with sodium dodecyl‐sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). The optimum pH was 6.5 for Lacc and LiP, and 3.0 for MnP, with an optimum temperature of 40 °C. The partially purified laccase had Km of 0.044 mmol L−1/min and Vmax of 222.22 U/mL. Ca2+ and Mn2+ ions increased ligninozyme activity with an increase in concentration from 0.5–5 mmol L−1. Cu2+ ions inhibited ligninozyme activity. The ligninozyme‐assisted pretreatment of wheat straw, rice straw, corn stover, and corn cobs revealed delignification in the range of 70 to 80.3%. The corresponding cellulose and hemicellulose recovery ranged between 58.5 to 65.4% and 38.4 to 47.6%, respectively. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

Optimization and Implementation of Fed-Batch Strategy to Produce Ligninolytic Enzyme from the White-Rot Basidiomycete Pycnoporus sanguineus in Bubble Column Reactor

The current work evaluates the production of ligninolytic enzyme optimization via response surface methodology using different inducers: acid cellulignin (CA); MnSO4 (Mn2+); CuSO4·5H2O (Cu2+); veratryl (3, 4-dimethoxybenzyl); alcohol (VA); Tween 80% (T80); and the carbon-to-nitrogen ratio (C/N). A further goal was implementing a fed-batch strategy to produce ligninolytic enzyme extracts from P. sanguineus 2512 using a bubble column reactor (BCR). The best optimized experimental condition in the shake flasks was a 7.5 C/N ratio, 0.025 g/L Cu2+, 1.5 mM Mn2+, 3.0 mM VA and 0.025 mM T80, resulting in 64,580, 9.10 and 80.72 U/L for Laccase (Lac), Manganese (MnP) and Lignin peroxidase (LiP) activities, respectively. In the BCR, three feedings were performed at 24 h intervals on the 6th, 7th and 8th days with a significant increase in Lac (99,600 U/L) and MnP (47.53 U/L) activities on the 8th day and a reduction on the 9th day of cultivation. The LiP activity peak was achieved on the 5th day (416 U/L) of cultivation, decreasing thereafter. Enzyme cocktails concentrated in hollow fiber in the third cultivation batch showed contents of 4 × 105 U/L, 220 U/L and 2.5 g/L for Lac, MnP and total proteins, respectively. The enzymatic cocktail with the highest LiP activity (1200 U/L) was obtained in the first batch. The results showed that the optimization of the biosynthesis of the ligninolytic enzymes provided satisfactory improvement in terms of Lac and MnP production per run.

High Level of Iron Inhibited Maize Straw Decomposition by Suppressing Microbial Communities and Enzyme Activities

In order to study the linkages between the crop straw decomposition rate and the change in soil biological properties after the straw returned to the soil with different iron (Fe2+) contents, a 180-day incubation experiment was performed to examine the decomposition of maize straw (MS) under three Fe2+ levels, i.e., 0, 0.3, and 1 mg g−1. Enzyme activities regarding straw decomposition and microbial communities under 0 and 1 mg g−1 Fe addition were also detected. The results showed that Fe2+ addition significantly inhibited MS decomposition. This was evidenced by the higher contents of hemicellulose, cellulose, and lignin in Fe2+ treatments on day 180. High-Fe addition (1 mg g−1) decreased the activity of Laccase (Lac) by 71.82% compared with control on day 30. Furthermore, the principal coordinates analysis (PCoA) indicated that high-Fe mainly affected the bacterial community. In particular, it suppressed the relative abundance of Microbacteriaceae in phylum Actinomycota that, in turn, is a potential decomposer of crop straw by secreting lignocellulolytic enzymes. A high level of Fe2+ inhibited the decomposition of hemicellulose, cellulose, and lignin in MS by reducing the relative abundance of phylum Actinobacteria in bacteria and suppressing Lac activity. Our findings provide guidance for returning crop straws in soils with high-Fe content.

Improved laccase production in Pleurotus djamor RP by atmospheric and room temperature plasma (ARTP) mutagenesis

BackgroundPleurotus djamor is an edible mushroom with medicinal properties, and degrades lignocellulose by producing enzymes that have a variety of industrial applications. The aim of this study was to improve laccase producing potential of P. djamor that may easily convert lignocellulose waste into high-value products. ResultsIn the present study, protoplast of the newly isolated fungus P. djamor RP was mutated by atmospheric pressure and room temperature plasma (ARTP) method. Guaiacol was used as an indicator for the rapid visual appearance of laccase positives in the screening process. From the results of preliminary screening, 10 promising positive mutants with a maximum laccase production were selected for further experimentation. Lac activity by the ABTS method showed that the mutant P. djamor strain 51-4 exhibited the maximum laccase production of 494.44 U/L in shake flask cultivation, which was 86.36% higher than wild strain. Notably, the other mutant P. djamor strain 62-27 exhibits a higher laccase production of 26.06 U/g which was 30.28% higher than wild strain when grown on solid-state fermentation. In addition to a higher yield of laccase, all mutants showed better growth and genetic stability than the wild strain. ConclusionsP. djamor RP mutants with high laccase-producing potential were developed by ARTP Mutagenesis technique, and these isolates could be used as a possible candidate for lignocellulose conversion into high-value products.How to cite: Zhang Z, Shah AM, Mohamed H, et al. Improved laccase production in Pleurotus djamor RP by atmospheric and room temperature plasma (ARTP) mutagenesis. Electron J Biotechnol 2022;58. https://doi.org/10.1016/j.ejbt.2022.03.005

Inhibition of miR397 by STTM technology to increase sweetpotato resistance to SPVD

As a critical food crop, sweetpotato (Ipomoea batatas (L.) Lam.) is widely planted all over the world, but it is deeply affected by Sweetpotato Virus Disease (SPVD). The present study utilized short tandem target mimic (STTM) technology to effectively up-regulate the expression of laccase (IbLACs) by successfully inhibiting the expression of miR397. The upstream genes in the lignin synthesis pathway were widely up-regulated by feedback regulation, including phenylalanine ammonialyase (PAL), 4-coumarate-CoAligase (4CL), hydroxycinnamoyl CoA:shikimatetransferase (HTC), caffeicacid O-methyltransferase (COMT), and cinnamyl alcohol dehydrogenase (CAD). Meanwhile, the activities of PAL and LAC increased significantly, finally leading to increased lignin content. Lignin deposition in the cell wall increased the physical defence ability of transgenic sweetpotato plants, reduced the accumulation of SPVD transmitted by Bemisia tabaci (Gennadius), and promoted healthy sweetpotato growth. The results provide new insights for disease resistance breeding and green production of sweetpotato.

Fungi Dekomposer Penghasil Enzim Ekstraseluler Lakase, Mangan Peroksidase, dan Lignin Peroksidase dari Kawasan Kebun Raya Bogor: Isolasi, Seleksi, Identifikasi dan Kajian Aktivitas Enzimnya

This study aimed to obtain the candidate isolates of superior decomposer from several plant block areas in the Bogor Botanic Gardens (KRB). Those candidates were expected to be able to utilize in the fermentation process of solid organic waste. The superior decomposer fungi candidates were selected based on their abilities to produce extracellular enzymes (laccase - Lac, manganese peroxidase - MnP, and lignin peroxidase - LiP) using 0.05% guaiacol as a substrate. The highest abundance of decomposer population was found in the block 4 with 9.9 x 106 CFU ml-1, and the lowest in block 6 with 1.9 x 106 CFU ml-1 density. Three superior decomposer isolates were obtained, namely KRB 3.1 (from block area 3), KRB 4.6 (from block area 4), KRB 6.7 isolate (from block area 7). The KRB 6.7 isolate has the highest Lac and MnP enzyme activities, as the following 24.10 U ml-1 and 186.3 U ml-1, while KRB 3.1 isolate from block area 3 has the highest LiP activity with the value 598.57 U ml-1. According to the molecular analysis, those candidate isolates of superior decomposers were identified as Coriolopsis hainanensis (KRB 3.1 isolate), Polyporus thailandensis (KRB 4.6 isolate), and Cerrena aurantiopora (KRB 6.7 isolate). Those are potentially used as the decomposers in solid organic waste fermentation.

Enhanced lignin biodegradation by consortium of white rot fungi: microbial synergistic effects and product mapping

BackgroundAs one of the major components of lignocellulosic biomass, lignin has been considered as the most abundant renewable aromatic feedstock in the world. Comparing with thermal or catalytic strategies for lignin degradation, biological conversion is a promising approach featuring with mild conditions and diversity, and has received great attention nowadays.ResultsIn this study, a consortium of white rot fungi composed of Lenzites betulina and Trametes versicolor was employed to enhance the ligninolytic enzyme activity of laccase (Lac) and manganese peroxidase (MnP) under microbial synergism. The maximum enzymatic activity of Lac and MnP was individually 18.06 U mL−1 and 13.58 U mL−1 along with a lignin degradation rate of 50% (wt/wt), which were achieved from batch cultivation of the consortium. The activities of Lac and MnP obtained from the consortium were both improved more than 40%, as compared with monocultures of L. betulina or T. versicolor under the same culture condition. The enhanced biodegradation performance was in accordance with the results observed from scanning electron microscope (SEM) of lignin samples before and after biodegradation, and secondary-ion mass spectrometry (SIMS). Finally, the analysis of heteronuclear single quantum coherence (HSQC) NMR and gas chromatography–mass spectrometry (GC–MS) provided a comprehensive product mapping of the lignin biodegradation, suggesting that the lignin has undergone depolymerization of the macromolecules, side-chain cleavage, and aromatic ring-opening reactions.ConclusionsOur results revealed a considerable escalation on the enzymatic activity obtained in a short period from the cultivation of the L. betulina or T. versicolor due to the enhanced microbial synergistic effects, providing a potential bioconversion route for lignin utilization.