Production Of Ligninolytic Enzymes Research Articles

Aeration regime modifies ligninolytic enzyme production and biodegradation of reactive black 5 by immobilized Trametes versicolor

Aeration regime modifies ligninolytic enzyme production and biodegradation of reactive black 5 by immobilized Trametes versicolor

Exploring the potential of bacterial consortium for the treatment of paper mill effluent treatment through various treatment strategies and evaluation of their toxicity

Paper mill effluent containing kraft lignin (KL) and other toxic compounds poses serious environmental health concerns due to its potential for bioaccumulation. A prospective bacterial consortium is still needed for the remediation of paper mill effluent. Therefore, the current work aims to explore the potential of consortium, i.e. Bacillus cereus, B. paramycoides, and B. aryabhattai via different treatment strategies: batch, continuous, multipulse, and dissolved oxygen (DO) stat fed-batch for maximum detoxification of effluent under optimised conditions. A minimal salt medium containing 1.0 % glucose, 0.5 % ammonium nitrate, and pH 8.0 was the optimum condition for the consortium to degrade 1000 mg/L of kraft lignin in the effluent. Laboratory adaptation evolution (LAE) studies showed that the maximum number of bacterial generations was observed within 178 h at 5th cycle for 3000 mg/L kraft lignin. The maximum removal of KL, color, chemical oxygen demand (COD), biological oxygen demand (BOD), and total phenol by the dissolved oxygen stat fed-batch treatment strategy was 94 %, 86 %, 91 %, 90 %, and 97 %, respectively. Phytotoxicity testing of the consortium-treated effluent on Vigna radiata L., and Trigonella foenum-graecum L. revealed a reduction in phytotoxicity by ∼66 % and ∼68 %, respectively. The genotoxicity study on Allium cepa L. showed that the percent of aberrant cells with different chromosomal aberrations was decreased in consortium-treated effluent as compared to untreated effluent. This work provides a new insight and strategy for the paper mill effluent treatment at an industrial scale. Statement of environmental implicationThe paper mill effluent contains various hazardous compounds; chlorinated phenols, dioxins, kraft lignin, and endocrine disrupting compounds, when discharge from industries without proper treatment. This effluent causes mutagenic, clastogenic, carcinogenic, and endocrine-disrupting mechanisms in flora and fauna. This study provides a comparative performance evaluation of different treatment strategies: batch, continuous fed-batch, multipulse fed-batch, and dissolved oxygen stat fed-batch, for paper mill effluent treatment using a bacterial consortium for maximum removal of kraft lignin, color, chemical oxygen demand, total phenol concentration, and quantified ligninolytic enzyme production. Treated effluent showed a lesser phytotoxic and genotoxic effect. Therefore, the results of this study are suitable for environmental restoration. Significance of studyContrastingly, throughout this study, found that bacterial consortium have superior detoxifying qualities of paper mill effluent compared to pure cultures, via different treatment strategies: batch, continuous, multipulse, and dissolved oxygen stat fed-batch strategies under optimised conditions at lab scale. According to these results, such dissolved oxygen stat fed-batch strategy mediated treated effluent that promotes seed germination and showed a higher mitotic index of root cells of the plant in contrast to untreated effluent. Therefore, these treatment strategies are adequate, effective, and sustainable to reduce the significant pollution load in effluent.

Use of sawdust for production of ligninolytic enzymes by white-rot fungi and pharmaceutical removal.

Use of white-rot fungi for enzyme-based bioremediation of wastewater is of high interest. These fungi produce considerable amounts of extracellular ligninolytic enzymes during solid-state fermentation on lignocellulosic materials such as straw and sawdust. We used pure sawdust colonized by Pleurotus ostreatus, Trametes versicolor, and Ganoderma lucidum for extraction of ligninolytic enzymes in aqueous suspension. Crude enzyme suspensions of the three fungi, with laccase activity range 12-43 U/L and manganese peroxidase activity range 5-55 U/L, were evaluated for degradation of 11 selected pharmaceuticals spiked at environmentally relevant concentrations. Sulfamethoxazole was removed significantly in all treatments. The crude enzyme suspension from P. ostreatus achieved degradation of wider range of pharmaceuticals when the enzyme activity was increased. Brief homogenization of the colonized sawdust was also observed to be favorable, resulting in significant reductions after a short exposure of 5 min. The highest reduction was observed for sulfamethoxazole which was reduced by 84% compared to an autoclaved control without enzyme activity and for trimethoprim which was reduced by 60%. The compounds metoprolol, lidocaine, and venlafaxine were reduced by approximately 30% compared to the control. Overall, this study confirmed the potential of low-cost lignocellulosic material as a substrate for production of enzymes from white-rot fungi. However, monitoring over time in bioreactors revealed a rapid decrease in enzymatic ligninolytic activity.

Transforming lignin into value-added products: Perspectives on lignin chemistry, lignin-based biocomposites, and pathways for augmenting ligninolytic enzyme production

Transforming lignin into value-added products: Perspectives on lignin chemistry, lignin-based biocomposites, and pathways for augmenting ligninolytic enzyme production

Proximate analysis of lignocellulosic biomass and its utilization for production, purification and characterization of ligninolytic enzymes by Aspergillus flavus

Proximate analysis of lignocellulosic biomass and its utilization for production, purification and characterization of ligninolytic enzymes by Aspergillus flavus

Valorization of agro-residues for production of ligninolytic enzymes from Pleurotus spp. and their deployment in dye decolorisation

Valorization of agro-residues for production of ligninolytic enzymes from Pleurotus spp. and their deployment in dye decolorisation

Effect of Solid-state Fermentation Parameters on Growth of Interest and Environmental Enzyme Production with Aspergillus niger

Using residual biomass in biological processes is increasingly promoted to alleviate environmental impacts. However, the focus is mainly based on emerging technologies and limited resources, and the conditions of the technologies remain unclear. The objective of this research is to establish the conditions of a solid-state fermentation system (SSF) for the growth of fungal biomass and the production of ligninolytic enzymes of environmental interest using Aspergillus niger. In a screening step, the biomass and lipase enzyme expression of three A. niger strains obtained from different screening sites will be extended. In the second stage, the effect of packing density (ρs) and airflow (vvm) was evaluated through a 23, on the growth of fungal biomass, fiber degradation, and CO2 generation in a lipid-contaminated SSF system. The generation of biomass and the concentration of specific enzymatic activity (U/L) of lipase present a correlation for all the strains evaluated. It was estimated that the A. niger strain AN19bc isolated from sugarcane bagasse presents the highest accumulation of biomass and concentration of specific enzyme activity of lipase (0.027 U/L) after nine days. The most appropriate conditions for the production of fungal biomass of the AN19bc strain in an SSF system are presented with an airflow of 33.33 vvm and packing density ρs = 360 kg Mss/m3, levels with which Yx/s= 0.91 is reached. After the process, the solid support used in the SSF presents a change in composition, with the fiber being the component that suffers a considerable degradation of 78.70%.

Elucidating the role of media nitrogen in augmenting the production of lignin-depolymerizing enzymes by white-rot fungi.

Indigenous white-rot fungal isolates Schizophyllum commune, Phanerochaete chrysosporium, Ganoderma racenaceum, and Lentinus squarrosulus, demonstrating the ability to depolymerize lignin of the crop residues, were studied for their potential to produce ligninolytic enzymes using modified production media under conditions of limiting and excess nitrogen for higher enzymatic expressions. Secretome-rich media on the investigation confirmed the successful production of lignin-depolymerizing enzymes, viz. laccase, lignin peroxidase, manganese peroxidase, and versatile peroxidase. Production of laccases and peroxidases was statistically significant in nitrogen-limiting media with and without the substrate, across all white-rot fungal cultures at 95% confidence interval. Nitrogen-limiting media with the substrate on analysis extracellularly expressed 99.27 U of laccase and 68.48 U of manganese peroxidase in Schizophyllum commune, while 195.14 U of lignin peroxidase was produced by Phanerochaete chrysosporium. Lentinus squarrosulus expressed 455.34 U of laccase and 357.13 U of versatile peroxidase with 250.09 U of laccase and 206.95 U of manganese peroxidase produced by Ganoderma racenaceum for every milliliter of the media used. Nitrogen-limiting media triggered the production of laccase during the initial stages of growth while the expression of peroxidases was predominant at a later stage. Also, this media evinced increased enzymatic yields with low biomass content compared to nitrogen-excess conditions. The extant study confirmed the positive influence of nitrogen-limiting media in the efficient production of ligninolytic enzymes and their suggestive degradation potential for environmental pollutants, making these enzymes a safe, clean alternative to the use of chemicals and the media to be effective for large-scale production of ligninolytic enzymes. IMPORTANCE Lignin on account of its high abundance, complex polymeric structure, and biochemical properties is identified as a promising candidate in renewable energy and bioproduct manufacturing. However, depolymerization of lignin remains a major challenge in lignin utilization, entailing the employment of harsh treatments representing not only an environmental concern but also a waste of economic potential. Developing an alternative green technology to minimize this impact is imperative. Methods using enzymes to depolymerize lignin are the focus of recent studies. Current research work emphasized the efficient expression of the major lignin-depolymerizing enzymes: laccases, lignin peroxidases, manganese peroxidases, and versatile peroxidases from native isolates of white-rot fungus for several biotechnological applications as well as treatment of crop residues for use as ruminant feed in improving productivity. The importance of nitrogen in augmenting the expression of lignin-depolymerizing enzymes and providing a media recipe for the cost-effective production of ligninolytic enzymes is highlighted.

The use of newly isolated fungal cultures for the selective delignification of bamboo culms.

The screening of ligninolytic enzyme-producing fungal species in samples led to the identification of Paracremonium sp. LCB1, Clonostachys compactiuscula LCD1 and C. compactiuscula LCN1. Both these strains produced high levels of hemicellulase and ligninolytic enzyme production over a relatively short fermentation period of 3-5days while exhibiting very low levels of cellulase activity. The results of the tests indicated that co-culturing LCB1 and LCN1 enhanced the ability to degrade lignin, and the ideal degrading circumstances and internal degrading mechanism of combined fungi were examined. The results showed that under conditions of temperature (30°C), pH (5), culture time (40 d), solid-liquid ratio (1:2.5), the pretreatment of bamboo culms with a co-culture of LCB1 and LCN1 resulted in a pronounced 76.37% drop in lignin weight and a high lignin/cellulose loss ratio (>10). Fourier transform infrared spectroscopy, X-ray diffractometry, and scanning electron microscopy were used to characterize the physicochemical properties of these bio-pretreated bamboo culms, further confirming that LCB1 and LCN1 co-culture represents an effective approach to bamboo delignification.

Fungal Ligninolytic Enzymes and Their Application in Biomass Lignin Pretreatment.

Lignocellulosic biomass is a significant source of sustainable fuel and high-value chemical production. However, due to the complex cross-linked three-dimensional network structure, lignin is highly rigid to degradation. In natural environments, the degradation is performed by wood-rotting fungi. The process is slow, and thus, the use of lignin degradation by fungi has not been regarded as a feasible technology in the industrial lignocellulose treatment. Fungi produce a wide variety of ligninolytic enzymes that can be directly introduced in industrial processing of lignocellulose. Within this study, screening of ligninolytic enzyme production using decolorization of ABTS and Azure B dyes was performed for 10 fungal strains with potentially high enzyme production abilities. In addition to standard screening methods, media containing lignin and hay biomass as carbon sources were used to determine the change in enzyme production depending on the substrate. All selected fungi demonstrated the ability to adapt to a carbon source limitation; however, four strains indicated the ability to secrete ligninolytic enzymes in all experimental conditions-Irpex lacteus, Pleurotus dryinus, Bjerkandera adusta, and Trametes versicolor-respectively displayed a 100%, 82.7%, 82.7%, and 55% oxidation of ABTS on lignin-containing media and 100%, 87.9%, 78%, and 70% oxidation of ABTS on hay-containing media after 168 h of incubation. As a result, the most potent strains of fungi were selected to produce lignocellulose-degrading enzymes and to demonstrate their potential application in biological lignocellulose pretreatment.

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.

Biodecolorization of anthraquinone and azo dyes by dark septate endophytic fungi

Mycoremediation has been proposed as a useful approach for treating dye wastewater. In the present study, six dark septate endophytic (DSE) strains (KSP, CPP, PP, DD, K.III.3.4, and TKC) were evaluated for their ability to decolorize anthraquinone (RBBR) and azo (AB 113) dyes. The decolorization ability was evaluated in solid and liquid media in conjunction with ligninolytic enzyme production and fungal biomass dry weight. The results showed that all of the tested DSE fungi successfully decolorized 89 % of the RBBR and 97 % of the AB 113 dyes. Three selected DSE strains (KSP, PP, and CPP) demonstrated high decolorization of RBBR (74 %–99 %) and AB 113 (79 %–99 %) dyes at pH 3–11 while producing ligninolytic enzymes. The decolorization occurred through biosorption, biodegradation, and simultaneous detoxification of the dyes. These results suggest that the selected DSE fungi may have the potential to bioremediate dye wastewater, which is usually under alkaline pH.

Production of Ligninolytic Enzymes from Thermophilic Bacterial Strains Isolated from Palm Oil Wastes

The conversion of lignocellulosic biomass into bioethanol or biochemical products requires a crucial pre-treatment process to break down the recalcitrant lignin structure. Biological depolymerization of lignin using microbial enzyme appeared to be a promising pre-treatment alternative as it offers environmentally friendly treatment with lower energy requirements. In this study, three (3) thermophilic bacterial strains (S2, S11Y, S23) with lignin-degrading potential were previously isolated from palm oil wastes and identified as Stenotrophomonas sp., Bacillus subtilis, and Aeribacillus sp., respectively. These isolates demonstrated the capability to grow in a medium containing AL as the sole carbon source. Most isolates also demonstrated enzymatic activities toward lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lac) enzymes within a short period of 72 h. The highest LiP was secreted by strain S2 (70.97 ± 0.059 U/L), followed by S11Y (63.570 ± 0.021 U/L) and S23 (60.880 ± 0.042 U/L). MnP was generated with low activities of approximately 1.313 ± 0.037 U/L by S11Y, 0.364 ± 0.004 U/L by S2, and 0.215 ± 0.021 U/L by S23. For the Lac enzyme, low activities were detected only in S2 and S11Y, with 2.075 ± 0.612 U/L and 1.463 ± 0.116 U/L, respectively. This preliminary study appeared to show that the isolated thermophilic bacteria have the potential to be applied for lignin degradation application.

Lignin degradation by co-cultured fungi: current status and future perspectives

The lignocellulosic biomass is a highly abundant and renewable resource. However, its exploitation is limited by the recalcitrance of the lignin present in the plant cellwall. In the last three decades, fungal co-cultures have increasingly been applied to overcome lignin recalcitrance by enhancing the production of ligninolytic enzymes through microbial interactions. In this paper, we systematically compile studies on fungal co-cultures used in the degradation of lignin-containing substrates to clarify the advantages and limitations of this type of culture. Based on their different delignification rate potentials, co-cultures can be classified into synergistic, antagonistic, and neutral. Co-cultivation results are generally related to the balance or imbalance of antagonistic and synergistic effects arising from the specific compatibility between the species during the interaction. It is well known that the paired species and the microenvironmental system conditions are responsible for the reported degradations,however, the mechanisms underlying these interactions remain poorly understood. In conclusion, literature results demonstrate the promising application of fungalco-cultures in biotechnological sectors to improve the degradation of lignin and its derivatives, through their better understanding of the efficient exploitation ofbiological resources on ecological and industrial scales.

Isolation and test of novel yeast strains with lignin usage capability and phenolic compound resistance.

Five yeast fungi strains (i.e., two Cryptococcus albidus, one Candida guillermondii, and two Candida tropicalis) were isolated from sugarcane and tested for their use of lignin as sole carbon source and their potential to grow in the presence of phenol and phenol derivatives (i.e., pentachlorophenol and p‐nitrophenol). The full set of isolated yeasts showed ligninolytic activity, achieving at least 36% lignin degradation after 25 days. The C. albidus JS‐B1 strain had the highest ligninolytic activity, achieving 27% lignin degradation within 4 days. This increased activity was associated with the production of ligninolytic laccase enzymes. All the tested yeast fungi strains showed growth in the presence of high concentrations of phenolic compounds (i.e., 900 mg/L phenol, 200 mg/L p‐nitrophenol, 50 mg/L pentachlorophenol) and showed significant potential for lignin and lignin by‐product degradation. Each of these five strains has the potential to be used in biological treatment processes for contaminated effluents from paper pulping and bleaching or phenol and phenol‐derivative biodegradation processes for other industrial wastewater effluents.

Degradation and decolourization potential of ligninolytic enzyme producing Bacillus paramycoides BL2 and Micrococcus luteus BL3 for pulp paper industrial effluent and its toxicity evaluation

Aim of this study was to optimize the production of Ligninolytic enzyme for the degradation of complex pollutants present in pulp paper industrial effluent (PPIE). Two ligninolytic enzyme-producing bacterial strains were isolated from PPIE and identified as Bacillus paramycoides strain BL2 (MZ676667) and Micrococcus luteus strains BL3 (MZ676668). The identified bacterial strain Bacillus paramycoides strain BL2 showed optimum production of LiP (4.30 U/ml), MnP (3.38 U/ml) at 72h of incubation, while laccase (4.43 U/ml) at 96h of incubation. While, Micrococcus luteusstrains BL3 produced maximum LiP (3.98) and MnP (3.85 U/ml) at 96h of incubation and maximum laccase (3.85 U/ml) at 72h of incubation, pH 7-8, and temperatures of 30-35°C. Furthermore, in the presence of glucose (1.0%) and peptone (0.5%) as nutrient sources, the enzyme activity of consortium leads to reduction of lignin (70%), colour (63%) along with COD (71%) and BOD (58%). The pollutants detected in control i.e. 3.6-Dioxa-2,7-disilaoctane, 2-Heptnoic acid,trimethylsilyl ester, 7-Methyldinaphtho [2,1-b,1',2'-d] silole, Hexadeconoic acid, trimethylysilyl ester, Methyl1(Z)-3,3-dipheny.1-4-hexenoale, 2,6,10,14,18,22-Tetracosahexane,2,2-dimethylpropyl(2Z,6E)-10,11epoxy5,6 Dihyrostigmasterol, acetate were completely diminished. The toxicity of PPIE was reduced up to 75%. Hence, knowledge of this study will be very useful for industrial sector for treatment of complex wastewater.

Biotransformation of bisphenol F by white-rot fungus Phanerochaete sordida YK-624 under non-ligninolytic condition.

Environmental bisphenol F (BPF) has a cyclic endocrine disruption effect, seriously threatening animal and human health. It is frequently detected in environmental samples worldwide. For BPF remediation, biological methods are more environmentally friendly than physicochemical methods. White-rot fungi have been increasingly studied due to their potential capability to degrade environmental pollutants. Phanerochaete sordida YK-624 has been shown to degrade BPF by ligninolytic enzymes under ligninolytic conditions. In the present study, degradation of BPF under non-ligninolytic conditions (no production of ligninolytic enzymes) was investigated. Our results showed that BPF could be completely removed after 7-d incubation. A metabolite of BPF, 4,4'-dihydroxybenzophenone (DHBP) was identified by mass spectrometry and nuclear magnetic resonance, and DHBP was further degraded by this fungus to form 4-hydroxyphenyl 4-hydroxybenzoate (HPHB). DHBP and HPHB were the intermediate metabolites of BPF and would be further degraded by P. sordida YK-624. We also found that cytochrome P450s played an important role in BPF degradation. Additionally, transcriptomic analysis further supported the involvement of these enzymes in the action of BPF degradation. Therefore, BPF is transformed to DHBP and then to HPHB likely oxidized by cytochrome P450s in P. sordida YK-624. Furthermore, the toxicological studies demonstrated that the order of endocrine-disrupting activity for BPF and its metabolites was HPHB > BPF > DHBP. KEY POINTS: • White-rot fungus Phanerochaete sordida YK-624 could degrade BPF. • Cytochrome P450s were involved in the BPF degradation. • The order of endocrine disrupting activity was: HPHB > BPF > DHBP.

PRODUCTION OF BACTERIAL LIGNINOLYTIC ENZYMES AND THEIR POTENTIAL APPLICATION IN DECOLORIZATION OF DYES

Lignin is a complex, three-dimensional aromatic polymer, consisting of dimethoxylated, monomethoxylated and non-methoxylated phenylpropanoid subunits, and is recalcitrant in nature. In this study, the isolation of lignin degrading bacteria was carried out from decaying wood samples. Ligninolytic activity was evaluated by growing bacterial isolates on lignin monomers and by the degradation of indicator dyes. Out of 16, the bacterial isolates L8, L12, L13 and L15 exhibited growth on monomers viz., vanillin, veratryl alcohol, phenol, guaiacol and lignin, with efficient dye decolourization. Further, the production of ligninolytic enzymes (laccase, lignin peroxidase and manganese) was estimated for the 4 selected bacterial isolates. The maximum enzymatic activity response was noted in the case of isolate L15, with the best growth on every lignin monomer.

Bundling the removal of emerging contaminants with the production of ligninolytic enzymes from residual streams

Enzymes offer interesting features as biological catalysts for industry: high specificity, activity under mild conditions, accessibility, and environmental friendliness. Being able to produce enzymes in large quantities and having them available in a stable and reusable form reduces the production costs of any enzyme-based process. Agricultural residues have recently demonstrated their potential as substrates to produce ligninolytic enzymes by different white rot fungi. In this study, the biotechnological production of a manganese peroxidase (MnP) by Irpex lacteus was conducted through solid-state fermentation (SSF) with wheat straw as substrate and submerged fermentation (SmF) employing wheat straw extract (WSE). The obtained enzyme cocktail also showed manganese-independent activity (MiP), related to the presence of a short MnP and a dye-decolorizing peroxidase (DyP) which was confirmed by shotgun proteomic analyses. In view of the enhanced production of ligninolytic enzymes in SmF, different parameters such as WSE concentration and nitrogen source were evaluated. The highest enzyme titers were obtained with a medium formulated with glucose and peptone (339 U/L MnP and 15 U/L MiP). The scale-up to a 30 L reactor achieved similar activities, demonstrating the feasibility of enzyme production from the residual substrate at different production scales. Degradation of five emerging pollutants was performed to demonstrate the high oxidative capacity of the enzyme. Complete removal of hormones and bisphenol A was achieved in less than 1 h, whereas almost 30% degradation of carbamazepine was achieved in 24 h, which is a significant improvement compared to previous enzymatic treatments of this compound.Key points• Wheat straw extract is suitable for the growth of I. lacteus.• The enzyme cocktail obtained allows the degradation of emerging contaminants.• Mn-dependent and Mn-independent activities increases the catalytic potential.Graphical abstract

Effect of lignocellulosic materials and chlorpyrifos pesticide on secretion of ligninolytic enzymes by the white rot fungus – Stereum ostrea

The present study compared the effect of chlorpyrifos on secretion of ligninolytic enzyme by the white rot fungus – Stereum ostrea grown in the presence and the absence of Tectona grandis cubes under submerged liquid conditions. Significantly higher yields of laccase and manganese peroxidase to the extent of 164.30 and 59.28 U/ml were registered in control containing only teak wood cubes than in the culture on combination of cubes and chlorpyrifos with 111.65 and 47.24 U/ml, respectively on 10th day of incubation. Reversed pattern in lignin peroxidase secretion with peak values on 6th day of incubation was noticed in the culture of S. ostrea immobilized on Tectona grandis cubes under influence of chlorpyrifos. Under free state conditions, significantly higher secretions of laccase (125.33 U/ml) and manganese peroxidase (53.60 U/ml) occurred in chlorpyrifos-amended medium than in the medium devoid of chlorpyrifos on 10th day incubation. Under moderate shaking conditions, supplementation of wheat bran alone at 3% level to the medium resulted in enhanced (3–5 folds) secretions of laccase, manganese peroxidase and lignin peroxidase by S. ostrea in medium free of wheat bran on 12th and 10th day of incubations. The presence of chlorpyrifos in addition to wheat bran in the medium further raised production of ligninolytic enzymes – laccase, MnP and LiP to the level of 311.78, 130 and 3 U/ml respectively on the 12th (higher LAC and MnP secretions) and 10th (higher LiP secretions) day of incubations. Our data in the present study suggest that secretion of ligninolytic enzymes by the culture is dependent on the nature of lignocellulosic material used in the study and secretion of higher titers of ligninolytic enzymes on cubes of Tectona grandis in the absence of chlorpyrifos rather in the presence of chlorpyrifos occurred. For executing microbial applications, it is critical to understand how lignocellulosic materials and toxic xenobiotic pesticides interact with white rot fungi and possible role of ligninolytic enzymes in the bioremediation process.