Production Of Ligninolytic Enzymes Research Articles

Development of biocomposites based on bacterial cellulose reinforced delignified rice husk-PVA plasticized with glycerol

Eco-friendly materials production from industrial wastes and renewable raw materials is being promoted for green construction applications. Therefore, considerable value can be added by combining green chemistry with microbial biotechnology to construct improved and far better, biologically stable, and compatible materials. For this purpose, herein, Schizophyllum commune IBL-06 was exploited for the production of ligninolytic enzymes (MnP, LiP, and Lac). This in-house extracted enzymatic consortium was used for the delignification of pristine rice husk. The enhanced level of delignification (40.35%) was achieved with maximum cellulose exposure (from 32 to 72%). The delignified rice husk was further reinforced with bacterial cellulose from Acetobacter xylinum. Subsequently, biocomposites were prepared from both pristine and bacterially treated rice husk using compression molding technique. Glycerol/maleic anhydride combination was used as a plasticizer/compatibilizer and chitosan (10 wt.%) as a filler for newly developed biocomposite specimens. The newly synthesized biocomposite specimens were characterized using different imaging and analytical techniques including scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The characterization studies of newly developed biocomposites revealed significant improvement in morphological and mechanical properties of biocomposites. In addition, moderate increase in water uptake capacity was also observed due to the presence of hygroscopic filler among polymer matrix. In conclusion, the improved characteristics of newly developed biocomposites based on bacterial cellulose-reinforced delignified rice husk-PVA using chitosan filler suggest high throughput of enzymatic treatment for several industrial and biotechnological sectors.

Sequential production of ligninolytic, xylanolytic, and cellulolytic enzymes by Trametes hirsuta AA-017 under different biomass of Indonesian sorghum accessions-induced cultures

Biorefinery concept encourages agricultural sector for developing zero waste technology. Utilization of agricultural residues for producing valuable products has become an important strategy to be investigated. Sorghum (Sorghum bicolor L) biomass, as one of agricultural residues, is potentially of great significance as a lignocellulosic material for production of lignocellulolytic enzymessuch as Laccase (Lac), Manganese Peroxidase (MnP), and Lignin Peroxidase (LiP), Cellulases (Cel), and Xylanases (Xyl). In the present study, 13 Indonesian sorghum accessions (with different lignocellulosic characteristics) were investigated due to their potency as potential substrate for production ligninolytic, hemicellulolytic, and cellulolytic enzymes by Trametes hirsuta AA-017 which has ability to sequentially produce the enzymes. Three accessions (Samurai, 4183, Kawali) were found as most suitable materials for enzymes production by the fungus with highest enhancement were more than 8000 and 71-fold, respectively for Lac and MnP. Total lignin in the biomass has shown a positive correlation with Lac (Pearson coefficient = 0.630; P < 0.01) and MnP produced by the fungus (Pearson coefficient = 0.595; P < 0.01). Optimized fermentation (pH, substrate concentration, incubation times, and mineral inducers) has been also conducted with the maximum Lac, MnP, LiP, Cel, and Xyl were 25.7 × 103, 46.7 × 103, 91, 540, and 670 U/L. This is the first report of sequential production of ligninolytic, cellulolytic, hemicellulolytic enzymes by Trametes hirsuta AA-017 using Indonesian sorghum biomass and its selective behaviour of the fungus on the biomass degradation. Sequential production of the enzymes have important economic benefits for production of biorefinery related enzymes.

Biodegradation of atrazine and ligninolytic enzyme production by basidiomycete strains

BackgroundAtrazine is one of the most widespread chlorinated herbicides, leaving large bulks in soils and groundwater. The biodegradation of atrazine by bacteria is well described, but many aspects of the fungal metabolism of this compound remain unclear. Thus, we investigated the toxicity and degradation of atrazine by 13 rainforest basidiomycete strains.ResultsIn liquid medium, Pluteus cubensis SXS320, Gloelophyllum striatum MCA7, and Agaricales MCA17 removed 30, 37, and 38%, respectively, of initial 25 mg L− 1 of the herbicide within 20 days. Deficiency of nitrogen drove atrazine degradation by Pluteus cubensis SXS320; this strain removed 30% of atrazine within 20 days in a culture medium with 2.5 mM of N, raising three metabolites; in a medium with 25 mM of N, only 21% of initial atrazine were removed after 40 days, and two metabolites appeared in culture extracts. This is the first report of such different outcomes linked to nitrogen availability during the biodegradation of atrazine by basidiomycetes. The herbicide also induced synthesis and secretion of extracellular laccases by Datronia caperata MCA5, Pycnoporus sanguineus MCA16, and Polyporus tenuiculus MCA11. Laccase levels produced by of P. tenuiculus MCA11 were 13.3-fold superior in the contaminated medium than in control; the possible role of this enzyme on atrazine biodegradation was evaluated, considering the strong induction and the removal of 13.9% of the herbicide in vivo. Although 88% of initial laccase activity remained after 6 h, no evidence of in vitro degradation was observed, even though ABTS was present as mediator.ConclusionsThis study revealed a high potential for atrazine biodegradation among tropical basidiomycete strains. Further investigations, focusing on less explored ligninolytic enzymes and cell-bound mechanisms, could enlighten key aspects of the atrazine fungal metabolism and the role of the nitrogen in the process.

Light Regulation of Two New Manganese Peroxidase-Encoding Genes in Trametes polyzona KU-RNW027.

To better understand the light regulation of ligninolytic systems in Trametes polyzona KU-RNW027, ligninolytic enzymes-encoding genes were identified and analyzed to determine their transcriptional regulatory elements. Elements of light regulation were investigated in submerged culture. Three ligninolytic enzyme-encoding genes, mnp1, mnp2, and lac1, were found. Cloning of the genes encoding MnP1 and MnP2 revealed distinct deduced amino acid sequences with 90% and 86% similarity to MnPs in Lenzites gibbosa, respectively. These were classified as new members of short-type hybrid MnPs in subfamily A.2 class II fungal secretion heme peroxidase. A light responsive element (LRE), composed of a 5′-CCRCCC-3′ motif in both mnp promoters, is reported. Light enhanced MnP activity 1.5 times but not laccase activity. The mnp gene expressions under light condition increased 6.5- and 3.8-fold, respectively. Regulation of laccase gene expression by light was inconsistent with the absence of LREs in their promoter. Blue light did not affect gene expressions but impacted their stability. Reductions of MnP and laccase production under blue light were observed. The details of the molecular mechanisms underlying enzyme production in this white-rot fungus provide useful knowledge for wood degradation relative to illumination condition. These novel observations demonstrate the potential of enhancing ligninolytic enzyme production by this fungus for applications with an eco-friendly approach to bioremediation.

Bio-pulping: An energy saving and environment-friendly approach

AbstractPretreatment of wood or other raw material with white-rot fungi (WRF) prior to pulping is known as biopulping. Lignin and hemicelluloses are removed selectively during early growth of WRF that produces enriched cellulose, known as selective delignification. Biopulping is considered as environment-friendly and cost-effective approach for delignification of lignocellulosic raw materials. The delignification efficiency of WRF during biopulping is directly related to ligninolytic enzymes production that is influence by several factors such as fungal strain, nature of raw material, oxygen availability, moisture content, pH, temperature, source of nitrogen, presence of Mn++and Cu++ions. The WRF, especiallyCeriporiopsis subvermispora,Trametes versicolorandPhanerochaete chrysosporium, have been used dominantly for the purpose of biopulping. It is an energy saving process that also improves brightness of pulp and strength properties including tensile index, burst index and folding endurance of paper. Significant decrease in kappa number has also been attained by fungal pretreatment of raw materials. Biological pretreatment of raw material also reduces the requirement of pulping chemicals.

Enzyme estimation based on bacterial interactions with Pleurotus spp.

Lignocellulosic material is the most abundant renewable source composed of lignin, hemicelluloses and cellulose present on earth. Lignin acts as a physical barrier to underneath cellulose which can be used for the production of useful products. Some white rot fungi such as Pleurotus spp . has the capability of degradation due to the production of a plethora of ligninolytic enzymes. This degradation process can be improved by coculturing the Pleurotus spp . with lignin degrading bacterial spp. In this study, the coculturing of two bacterial spp. Bacillus and Delftia with Pleurotus spp . i.e. Pleurotus florida and Pleurotus sajor-caju was investigated. No antagonistic effect was observed in the interaction of the bacterial strains with fungal species. During ligninolytic enzyme production studies on Mushroom Minimal Media (MMM) containing paddy straw as an inducer, it was observed that enzyme production was more in media inoculated with bacterial species. Therefore, coculturing of the bacteria with Pleurotus can enhance the digestibility of the paddy straw.

Evaluación del consorcio entre Pleurotus ostreatus, Trametes versicolor y bacterias aeróbicas para remoción de colorantes sintéticos

Los residuos líquidos producidos al elaborar tinciones biológicas contienen mezclas de compuestos químicos y microorganismos, que generan un elevado impacto ambiental si no son tratados adecuadamente. Por esta razón, en el presente trabajo se evaluaron a Pleurotus ostreatus, Trametes versicolor, Enterobacter xianfangensis, Pseudomonas azotoformans, Pseudomonas sp., Bacillus subtilis y Pseudomonas fluorescens, para el tratamiento de un residuo líquido que contenía colorantes trifenilmetánicos y azóicos, a escala de laboratorio. Inicialmente, se seleccionaron las cepas con menor efecto antagónico y se determinó su potencial para producir las enzimas Lacasa, Manganeso Peroxidasa y Lignino Peroxidasa, al emplear sustratos inductores y mezclas de colorantes. Para el consorcio fúngico/bacteriano la disminución del color y demanda química de oxígeno fueron del 99 % y 70 % a las 96 h. La remoción de estos parámetros se relacionó con la interacción positiva entre las poblaciones de hongos, bacterias y la producción de enzimas ligninolíticas, obteniendo valores a las 96 h de 7.0 y 14.0 unidades logarítmicas para hongos y bacterias, con unas actividades enzimáticas de 75 U/L, 205 U/L y 0.63 U/L para Lacasa, MnP y LiP, respectivamente.

Isolation of Ligninolytic Enzymes Producing Microbes from Textile Effluent Contaminated Soil

Evaluation of some microbial species for their ability to produce ligninolytic enzymes was investigated using streak plate method. Ten (10) microbial strains were isolated from soil contaminated with textile effluents using the spread plate technique. Aspergillus terreus and Aspergillus niger showed higher expression for laccase with 8.0 mm diameter zones clearance. Bacillus licheniformis and Bacillus subtilis had the widest clearance zone (12.0 and 8.0 mm) respectively. Only Aspergillus flavus however had the potential to produce lignin peroxidase (with 10 mm zones of clearance) of all the fungi isolated in this study. Streptococcus faecalis, Trichoderma harzianum, Micrococcus luteus, and Aspergillus flavus had the widest clearance zones (6.0 mm) in the Manganese peroxidase screening medium.Some of the microbial species possessed multiple traits for the production of the various ligninolytic enzymes assayed at ≥8 mm diameter zone clearance. Therefore, the research main focus is to identify microorganisms that are potential producers ofligninolytic enzymesgiven that they can be used for industrial waste bioremediation.

Utilization of oil palm decanter cake for valuable laccase and manganese peroxidase enzyme production from a novel white-rot fungus, Pseudolagarobasidium sp. PP17-33.

Oil palm decanter cake (OPDC) in the current study was converted to valuable products as laccase and manganese peroxidase (MnP) by an undescribed strain of the white-rot fungus, Pseudolagarobasidium sp. PP17-33. The optimization to enhance the production of enzymes through solid-state fermentation was performed using Plackett-Burman design and response surface methodology. The highest observed laccase was 5.841 U/gds and observed MnP was 5.156 U/gds, which enhanced yield by 2.59-fold and 1.94-fold from the non-optimization. The optimized medium (mg/g of OPDC) consisted of 0.852mg CuSO4·5H2O, 13.512mg glucose, 2mg yeast extract, 0.2mg KH2PO4, 1.5mg MgSO4·7H2O, 0.01mg FeSO4·7H2O, 0.15mg MnSO4·H2O, 0.01mg ZnSO4·7H2O and 0.3mg Tween 80 (pH 5.0) when incubated at 30°C for 7days. The most significant variables of laccase and MnP productions were CuSO4·5H2O and glucose concentrations. This study is the first to report on the production of ligninolytic enzymes from OPDC waste using white-rot fungi. In addition, five different white-rot fungi, Coriolopsis aspera, C. retropicta, Dentipellis parmastoi, Nigroporus vinosus and Tyromyces xuchilensis, are newly observed producers of ligninolytic enzymes in Thailand. The results obtained from this study are significant not only for agro-industrial waste management but also for value-added enzyme production.

Nitrogen sources and trace elements influence Laccase and peroxidase enzymes activity of Grammothele fuligo

The effect of different organic, inorganic nitrogen sources and trace elements on growth and ligninolytic enzymes production by Grammothele fuligo has been investigated. Amongst all the nitrogen compounds used, the most favourable for growth was ammonium oxalate. It showed maximum Lignin Peroxidase activity (80.6 IU/mL) with ammonium chloride. The optimum Manganese Peroxidase activity (4.13 IU/mL) was observed with ammonium acetate. DL-alanine served as the best organic nitrogen source for the growth. The highest MnP (36.7 IU/mL) and laccase (3921.5 IU/mL) activities were revealed in medium supplemented by DL-tryptophan. However, their positive effects on enzyme accumulation were due to a higher biomass production. The higher concentrations of trace elements were found to be fungistatic for its growth viz. B, Co, Cu, Fe (400 ppm) and Co (100 ppm). It exhibited maximum LiP activity (456.9 IU/mL) with 10−3 ppm Fe and MnP activity (3.30 IU/mL) with 10−6 ppm B and 10−3 ppm Ca. The maximum laccase activity (653.5 IU/mL) was observed with 10−6 ppm Cu. This is the first report on nitrogen sources and trace elements effect on ligninolytic enzymes production of Grammothele. The results will facilitate research to understand the nature of the fungus and to increase its enzymes production under controlled conditions.

Use of Palm Empty Fruit Bunches for the Production of Ligninolytic Enzymes by Xylaria sp. in Solid State Fermentation

Palm empty fruit bunches (PEFB) as a cheap substrate for the production of ligninolytic enzymes was investigated using Xylaria sp. BCC 7794 in solid state fermentation. To improve the enzyme production, the optimization was carried out with one factor-at-a-time method. It was found that Xylaria sp. BCC 7794 cultivated in PEFB with the 7% (w/w) wheat starch as co-substrate, the initial moisture content of 70% and the six agar plugs of inoculum for 12 days gave the highest ligninolytic enzymes production. Moreover, the statistic methods using Box-Behnken design was conducted to investigate the optimum nitrogen and CuSO4 concentration for the enzyme production. The maximum laccase and MnP activity of 16.3 and 24.8 U/gPEFB, respectively was achieved at 2.06 g/l (NH4)2H2PO4 (DAHP), 1.07 g/l urea and 5.22 mg/l CuSO4·5H2O. The optimum temperature and pH for the production of ligninolytic enzymes was at 25 °C and pH 5.0–6.0. In addition, it was found that Xylaria sp. BCC 7794 produced hydrolytic enzymes including CMCase, FPase, xylanase and β-glucosidase at 9.93, 0.49, 9.23 and 21.5 U/g PEFB, respectively. Selectivity values of 0.9 was also found with the lignin and cellulose degradation of 16.2 and 18.0%, respectively. PEFB had the potential to use as low cost substrate for the production of ligninolytic enzymes.

Upscale and characterization of lignin-modifying enzymes from Marasmiellus palmivorus VE111 in a bioreactor under parameter optimization and the effect of inducers

Testing different pHs, dissolved oxygen concentrations and temperatures, plus the addition of inducers, to optimize ligninolytic enzyme activity, resulted in increased production of laccases, total peroxidases and manganese peroxidases on the order of 2.1-fold, 4.6-fold and 10-fold, respectively; laccases reached 6588 U/mL, total peroxidases reached 3533 U/mL and manganese peroxidase achieved 60 U/mL. Furthermore, an increase in laccase volumetric productivity and in its specific activity was verified. The addition of inducers, such as copper sulphate and manganese sulphate, improved enzymatic activity. In addition, a new previously unidentified laccase isoform was documented by zymography. The present work successfully increased the production of ligninolytic enzymes.

Production of Ligninolytic Enzymes by Coptotermes curvignathus Gut Bacteria

Abstract Maximum utilization of lignocellulosic biomass is contingent upon degrading the recalcitrant lignin polymer. Conventional methods employed in delignification require high inputs of energy and chemicals, resulting in the release of highly toxic effluents. The ability of gut flora of Coptotermes curvignathus in lignin degradation was investigated in this study. Production of ligninolytic enzymes was done in an aerated submerged fermentation system with kraft lignin as sole carbon source. The degradation experiment was carried out for 7 days at 30 °C, pH 7. Three potential lignin degraders identified as Bacillus sp., Lysinibacillus sp. and Acinetobacter sp. were successfully isolated. The bacterial growth and secretion of extracellular ligninolytic enzymes confirmed metabolism of kraft lignin by the identified strains. Lysinibacillus sp., a novel lignin degrader showed highest manganese peroxidase (76.36 ± 15.74 U/L) and laccase activity (70.67 ± 16.82 U/L) after 7 and 6 days of incubation respectively, while maximal activity of lignin peroxidase (262.49 ± 0.92 U/L) was recorded after 7 days in culture supernatants of Bacillus sp. With respect to the activity of the secreted enzymes, the lignin degrading potential of these bacterial strains can be explored in the valorisations of lignocellulosic biomass in industrial processes such as pulping, bioethanol production, fine chemicals and materials synthesis.

Oxidative enzymes activity and hydrogen peroxide production in white-rot fungi and soil-borne micromycetes co-cultures

Fungal co-cultures appear to be advantageous for ligninolytic enzyme (LE) production compared to single fungal strains. The aims of this study were (1) to determine the type of fungal interactions in the co-cultures of two white-rot fungi (WRF, Pycnoporus sanguineus and Trametes maxima) and eight soil-borne micromycetes (SBM), (2) to determine the laccase and manganese peroxidase (MnP) activities and the hydrogen peroxide (H2O2) production in two compatible fungal and micromycetic co-cultures in submerged fermentation, and (3) to understand the effect of H2O2 on LE production by WRF through a dose-response bioassay. In the co-culture of SBM and Pycnoporus sanguineus, the main interaction was deadlock at a distance, whereas T. maxima showed competitive antagonism and replaced the SBM. In the agar plates, Purpureocillium lilacinum (27.8-fold increase) and Beauveria brongniartii (9.4-fold increase) enhanced the laccase and MnP activities of P. sanguineus, and Metarhizium anisopliae (Ma129) (0.83-fold increase) and Trichoderma sp. SP6 (22.6-fold increase) similarly enhanced these activities in T. maxima. In submerged fermentation, P. lilacinum also increased the laccase and MnP activities of P. sanguineus. The laccase activity of T. maxima only increased in the co-culture with B. brongniartii. The co-cultures achieved higher H2O2 production compared to the WRF monoculture, which played a vital role in the increase of LE. The dose-response assays revealed that low concentrations of H2O2 (2.94 and 14.69 mM) enhance the laccase and MnP activities in WRF.

Pulp wash: a new source for production of ligninolytic enzymes and biomass and its toxicological evaluation after biological treatment

ABSTRACTPulp wash was used as substrate for the activity of ligninolytic enzymes of the fungus Pleurotus sajor-caju. Activity of laccase (Lac) and manganese peroxidase (MnP) as well as fungal biomass occurred under four conditions: different pulp wash concentrations, pH variation at the optimal pulp wash concentration, different glucose concentrations, and different concentrations of ammonium nitrate. The best enzyme activity and biomass production were obtained with in natura pulp wash and pH corrected to 5.0 (4884 IU/L Lac; 82 IU/L MnP; 25 g/100 mL biomass). However, the addition of glucose and ammonium nitrate to the pulp wash was not necessary for increasing the enzyme activity and biomass production. Efficient removal of pulp wash chemical oxygen demand (99.66%) and biochemical oxygen demand (83.27%) occurred after the mycoremediation with P. sajor-caju in the optimized conditions. Lactuca sativa L. seeds germination bioassay showed a four-fold reduction in the residue toxicity (EC50 28.72%) after the treatment with the fungus. Our findings are consistent with the notion that pulp wash is an excellent substrate for inducing the activity of ligninolytic enzymes and producing fungal biomass, and that the biological treatment is efficient to reduce effluent toxicity.

Sustainable bioremediation of sugarcane vinasse using autochthonous macrofungi

Vinasse is the main residue from bioethanol production. If discharged in water bodies, it can impair the photosynthetic process causing great damage to the environment. However, this wastewater could be considered a by-product and used as a substrate for obtaining value-added products. In the present work, two basidiomycetous fungi were selected based on their ability to decolorize vinasse and to synthesize lignocellulolytic enzymes in agar medium. Selected fungi were identified as Pycnoporus sp. P6 and Trametes sp. T3. In liquid cultures, both fungi demonstrated their capacity to decolorize and remove phenolic compounds from diluted vinasse, with the concomitant production of ligninolytic enzymes, mainly laccases, suggesting the participation of this enzyme in the bioremediation process. This study proposes that Pycnoporus sp. P6 and Trametes sp. T3 could be used in the design of cutting-edge sustainable biotechnological processes to remedy vinasse, simultaneously synthesizing oxidative enzymes, in an environmentally friendly way.

Application of ligninolytic enzyme of Lentinus polychrous on synthetic dye decolorization

Contamination of water resources by synthetic dyes causes many environmental and health problems. Fungal ligninolytic enzymes have been applied for dye decolorization due to its ability in degrading a wide variety of recalcitrant substances. Extracellular ligninolytic enzyme production by white rot fungus, Lentinus polychrous, grown in glucose containing medium supplemented with rice straw powder and soybean pomace was monitored. Optimum condition for remazol brilliant blue R (RBBR) decolorization was studied by varying initial RBBR concentrations, pH values, and initial crude enzyme concentrations. The result revealed that the ligninolytic enzyme dominantly produced was laccase with an activity of 0.095 U/ml on day 15, and a small amount of manganese peroxidase was also detected. The crude laccase produced from L. polychrous, effectively decolorized the dye within a short period of time, that was approximately 50% of 20 mg/l RBBR was decolorized within the first 2 hours. The optimal pH for RBBR decolorization was 3.0 which had an efficiency of 87% within 6 hours after incubation. Moreover, the best redox mediator of laccase was CuSO4, whose decolorization efficiency was over twice than that of samples without this mediator. The decolorization intensified with increase of CuSO4 concentration but higher concentrations of chromium tended to suppress decolorization.

Enhancement of ligninolytic enzymes production and decolourising activity in Leptosphaerulina sp. by co–cultivation with Trichoderma viride and Aspergillus terreus

This work investigated fungal co–culture as inducer of ligninolytic enzymes and decolourising activity in the Colombian strain Leptosphaerulina sp., an ascomycete white-rot fungus isolated from lignocellulosic material. Aspergillus niger, Aspergillus fumigatus, Aspergillus terreus, Trichoderma viride, Fusarium sp. and Penicillium chrysogenum were tested as Leptosphaerulina sp. inducers. The best fungal combinations in terms of enzyme production, fungal growth and decolourising activity were selected from solid media experiments. Response surface methodology (RSM) was utilised to optimise enzyme production and decolourising activity in liquid media. Solid media assays evidenced T. viride and A. terreus as the best Leptosphaerulina sp. inducers. The RSM identified a triple co–culture inoculated with T. viride (1000 μL) and A. terreus (1000 μL) into a 7–day culture of Leptosphaerulina sp. as the best treatment. This triple combination significantly improved ligninolytic enzymes production and Reactive Black 5 dye removal when compared to the Leptosphaerulina sp. monoculture and previously used chemical inducers. These results demonstrated the potential of fungal co–culture as an environmentally–friendly method to enhance Leptosphaerulina sp. enzymes production and decolourising activity.

Production of Ligninolytic Enzymes from Penicillium Sp. and Its Efficiency to Decolourise Textile Dyes

Background:The present study discussed the bio decolourization of synthetic textile dyes using extracellular crude laccase from an Ascomycetes fungusPenicilliumsp. Laccase based decolourization is found to be potentially advantageous to bioremediation technologies.Methods:In this study, the production of laccase was observed for 7 days of incubation under shaking conditions. Maximum laccase production was secreted by fungal strain on the 6thday of incubation under submerged fermentation. Incubation of fungal mycelium and culture filtrate as crude enzyme obtained fromPenicilliumsp. with textile dyes - Indigo, Reactive black-5, Acid blue -1 and Vat brown -5 on solid PDA medium and liquid PDA broth showed effective biological dye decolourisation.Result:Solid state dye decolourisation had shown 45%, 25%, 50% and 72% colour removal of dyes - Indigo, Reactive black-5, Acid blue -1 and Vat brown -5 whereas maximum decolourization of same dyes of 45%, 20%, 48%, and 75% was obtained in liquid state with crude enzyme within 3h.Conclusion:The results had shown the potential dye decolourisation capacity of thePenicilliumsp. extracellular crude laccase and pave a way to apply this strain on an industrial scale.

Biodelignification of some agro-residues by Stenotrophomonas sp. CFB-09 and enhanced production of ligninolytic enzymes

Abstract Biological delignification is an environmental friendly pretreatment method for enhanced enzymatic hydrolysis of lignocellulosic biomass and fermentation processes. In an attempt to optimize delignification process which is crucial for effective biofuel production from agro-residues, this study investigated biodelignification of some agro-residues (coconut shell {CS}, coconut husk {CH}, palm kernel shell {PKS}, oil palm empty fruit bunch {OPEFB} and sawdust {SD}) by Stenotrophomonas sp. CFB-09 under submerged fermentation conditions. Initial lignin and residual lignin contents of each agro-residue were determined at the beginning and end of 216 h biodelignification period. Production of ligninolytic enzymes was monitored at 12 h intervals. Effects of nitrogen sources, temperature and pH on production of ligninolytic enzymes were determined over the biodegradation period. Remarkably, biodelignification of the agro-residues was in the range of 41–55%. Laccase had highest yield (31 U/mg) on CH, PKS and OPEFB. Lignin peroxidase production (381 U/mg) was maximum on OPEFB, and manganese peroxidase had highest yield (53 U/mg) on PKS. Surprisingly, there was appreciable production of ligninolytic enzymes at higher temperatures of biodegradation with 40–55% yield at 80 °C. Maximum enzyme production was achieved at 40 °C, pH 8.0 with ammonium nitrate as nitrogen source. Results provide deeper insights into biodelignification of agro-residues and demonstrate potential of Stenotrophomonas sp. CFB-09 for use in biodegradation of agro-residues, especially in pretreatment of lignocellulosic biomasses for production of biofuel and other value-added products.