Solid-state fermentation for enhanced production of laccase using indigenously isolated Ganoderma sp

Wheat bran as an efficient agro-process waste for enhanced yellow laccase production by Lentinus tigrinus SSB_W2 and its application in anthraquinone dye degradation

Lentinus tigrinus SSB_W2, isolated from Mahabaleshwar in the Western Ghats of Maharashtra, India, was employed to enhance laccase production in solid-state fermentation (SSF). The spectral analysis indicated that the laccase produced by L. tigrinus is a typical yellow laccase, exhibiting no absorption at 600 nm. Notably, this yellow laccase demonstrated exceptional catalytic activity, as confirmed by electrochemical analysis. Four agricultural processing wastes were evaluated as substrates for SSF, and the results showed that L. tigrinus effectively utilized wheat bran. Initial testing by one-factor-at-a-time method showed 3.79-fold increase in yellow laccase production, which subsequently increased to 6.51-fold after Plackett-Burman design. Moreover, employing response surface methodology resulted in 11.87-fold increase (108,472 IU gds-1) in laccase production. The utilization of yellow laccase for the biotransformation of various textile dyes was investigated, and it exhibited the highest degradation efficiency toward Reactive blue 4, a recalcitrant anthraquinone dye, with a rate of 18.36 mg L-1 h-1, for an initial concentration of 1000 mg L-1.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03881-9.

Laccase production by Pleurotus ostreatus using cassava waste and its application in remediation of phenolic and polycyclic aromatic hydrocarbon-contaminated lignocellulosic biorefinery wastewater

The treatment of contaminants from lignocellulosic biorefinery effluent has recently been identified as a unique challenge. This study focuses on removing phenolic contaminants and polycyclic aromatic hydrocarbons (PAHs) from lignocellulosic biorefinery wastewater (BRW) applying a laccase-assisted approach. Cassava waste was used as a substrate to produce the maximum yield of laccase enzyme (3.9 U/g) from Pleurotus ostreatus. Among the different inducers supplemented, CuSO₄ (0.5 mM) showed an eight-fold increase in enzyme production (30.8 U/g) after 240 h of incubation. The catalytic efficiency of laccase was observed as 128.7 ± 8.47 S^-1mM^-1 for syringaldazine oxidation at optimum pH 4.0 and 40 °C. Laccase activity was completely inhibited by lead (II) ion, mercury (II) ion, sodium dodecyl sulphate, sodium azide and 1,4 dithiothretiol and induced significantly by manganese (II) ion and rhamnolipid. After treating BRW with laccase, the concentrations of PAHs and phenolic contaminants of 1144 μg/L and 46160 μg/L were reduced to 96 μg/L and 16100 μg/L, respectively. The ability of laccase to effectively degrade PAHs in the presence of different phenolic compounds implies that phenolic contaminants may play a role in PAHs degradation. After 240 h, organic contaminants were removed from BRW in the following order: phenol >2,4-dinitrophenol > 2-methyl-4,6-dinitrophenol > 2,3,4,6-tetrachlorophenol > acenaphthene > fluorine > phenanthrene > fluoranthene > pyrene > anthracene > chrysene > naphthalene > benzo(a)anthracene > benzo(a)pyrene > benzo(b)fluoranthene > pentachlorophenol > indeno(1,2,3-cd)pyrene > benzo(j) fluoranthene > benzo[k]fluoranthène. The multiple contaminant remediation from the BRW by enzymatic method, clearly suggests that the laccase can be used as a bioremediation tool for the treatment of wastewater from various industries.

The production of laccases by white-rot fungi under solid-state fermentation conditions

Laccases (E.C. 1.10.3.2) produced by white-rot fungi (WRF) can be widely used, but the high cost prevents their use in large-scale industrial processes. Finding a solution to the problem could involve laccase production by solid-state fermentation (SSF) simulating the natural growth conditions for WRF. SSF offers several advantages over conventional submerged fermentation (SmF), such as higher efficiency and productivity of the process and pollution reduction. The aim of this review is therefore to provide an overview of the current state of knowledge about the laccase production by WRF under SSF conditions. The focus is on variations in the up-stream process, fermentation and down-stream process and their impact on laccase activity. The variations of up-stream processing involve inoculum preparation, inoculation of the medium and formulation of the propagation and production media. According to the studies, the production process can be shortened to 5-7 days by the selection of a suitable combination of lignocellulosic material and laccase producer without the need for any additional components of the culture medium. Efficient laccase production was achieved by valorisation of wastes as agro-food, municipal wastes or waste generated from wood processing industries. This leads to a reduction of costs and an increase in competitiveness compared to other commonly used methods and/or procedures. There will be significant challenges and opportunities in the future, where SSF could become more efficient and bring the enzyme production to a higher level, especially in new biorefineries, bioreactors and biomolecular/genetic engineering.

Enrichment of laccase production by Phoma herbarum isolate KU4 under solid-state fermentation by optimizing RSM coefficients using genetic algorithm

The process parameters were optimized to obtain enhanced enzyme activity from the fungus Phoma herbarum isolate KU4 using rice straw and saw dust as substrate under solid-state fermentation using Response surface methodology (RSM). Genetic algorithm was used to validate the RSM for maximum laccase production. Six variables, viz., pH of the media, initial moisture content, copper sulphate concentration, concentration of tannic acid, inoculum concentration and incubation time were found to be effective and optimized for enhanced production. Maximum laccase production was achieved by RSM at pH 5·0 and 86% of initial moisture content of the culture medium, 150 µmol l^-1 of CuSO₄ , 1·5% tannic acid and 0·128 g inoculum g^-1 dry substrate inoculum size on the fourth day of fermentation. The highest laccase activity was observed as 79 008 U g^-1 , which is approximately sixfold enhanced production compared to the unoptimized condition (12 085·26 U g^-1 ).

Enhancement of Laccase Production by Optimizing the Cultural Conditions for Pleurotus sajor-caju in Solid-State Fermentation

Nowadays, a lot of interest has been given to the development of cost-effective and efficient enzyme production technologies. Laccase enzymes are widely used in biotechnological, environmental and industrial sectors. Due to the cost-effectiveness of the solid-state fermentation (SSF) process, it is widely used to produce a broad range of biological products. In this study, optimization of moisture content, temperature, pH, and inoculum size were studied to enhance laccase production ability of Pleurotus sajor-caju in SSF by using One Factor At Time (OFAT) and Response Surface Methodology (RSM). OFAT was used as a baseline study for deducing the experimental design of RSM. The highest production of laccase enzyme (1450 U/g) by Pleurotus sajor-caju on wheat straw was observed at 26°C, 6.0 pH, 72.5 % moisture content, 7.5% inoculum size, 1% fructose and 0.5 % peptone. Unlike the conventional inoculum preparation method, here the inoculum was generated by the spawning method for SSF. The molecular weight of partially purified laccase from Pleurotus sajor-caju was estimated to be around 62 K Da using SDS PAGE. The activity staining of laccase was observed as a zymogram on Native PAGE using ABTS as a substrate. Lignin degradation of wheat straw and its structural disruption due to laccase was observed by Scanning Electron Microscopy (SEM).

Bioprocess optimization of laccase production through solid substrate fermentation using Perenniporia tephropora-L168 and its application in bioremediation of triaryl-methane dye

Laccases are multi copper oxidases that can oxidize both phenolic and nonphenolic lignin related compounds. Consequently, there has been continuous demand for laccases for the oxidative degradation of phenolic dyes in effluents. In view of this, the present work was focused on laccase production by solid substrate fermentation using a newly isolated fungus Perenniporia tephropora-L168. To intensify the laccase production, the process parameters pH, nitrogen, inducer, and substrate: water ratio were optimized by using statistical model. A set of optimal conditions noted were pH 3, nitrogen 0.001 g/L; inducer 0.5% and substrate: water ratio (1:10), which yielded laccase 1,160 U/g. The crude laccase exhibited noteworthy potential to degrade a triaryl-methane dye especially Malachite green. Also, during bioremediation studies, the statistical process optimization could achieve 81% decolourization within 180 min. The laccase treatment brought chemical transformation in malachite green as evident from UV-Visible spectra, FTIR, HPLC while toxicity against bacteria and fungi was also reduced. During phytotoxicity study, effect of treated and untreated dye on germination of seed was analyzed. Interestingly, the germination index for Vigna aconitifolia and Vigna radiata was increased by two and fourfold, respectively. Overall, this work demonstrates optimized production of laccase using Perenniporia tephropora-L168 and its efficient bioremediation potential for triaryl-methane dye.

Pre-treatment of a sugarcane bagasse-based substrate prior to saccharification: Effect of coffee pulp and urea on laccase and cellulase activities of Pycnoporus sanguineus

Production of second-generation bioethanol uses lignocellulose from agricultural by-products such as sugarcane bagasse (SCB). A lignocellulose pre-treatment is required to degrade lignin, ensuring further efficient saccharification. Two experimental designs were set up to define culture conditions of Pycnoporus sanguineus in mesocosms to increase laccase activities and thus delignification. The first experimental design tested the effect of phenolic complementation (via coffee pulp) and the use of urea as a simple nitrogen source and the second defined more precisely the percentages of coffee pulp and urea to enhance delignification. The responses measured were: lignocellulolytic activities, laccase isoform profiles by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the chemical transformation of the substrate using solid-state NMR of 13C. Adding 10% of coffee pulp increased laccase activities and fungal biomass (32.5% and 16% respectively), enhanced two constitutive isoforms (R_f 0.23 and 0.27), induced a new isoform (R_f 0.19) and led to a decrease in total aromatics. However, higher concentrations of coffee pulp (25%) decreased laccase and cellulase activities but no decrease in aromaticity was observed, potentially due to the toxic effect of phenols from coffee pulp. Moreover, laccase production was still inhibited even for lower concentrations of urea (0-5%). Our findings revealed that an agricultural by-product like coffee pulp can enhance laccase activity -though to a threshold- and that urea limited this process, indicating that other N-sources should be tested for the biological delignification of SCB.

Response surface based optimization of laccase production from Bacillus sp. MSK-01 using fruit juice waste as an effective substrate

Laccases are multicopper oxidases containing four copper atoms per monomer distributed in three redox sites. Because of its tremendous applications in different areas, isolation of new laccases with wide range of industrial implementation. The present study focuses on the optimization of laccase production from Bacillus sp. MSK-01 under solid state fermentation conditions using fruit juice waste as the substrate. MSKLAC was produced extracellularly by the bacteria. This laccase was able to oxidize ABTS and syringaldazine. Various nutritional and environmental factors were utilized for increasing the enzyme yield. Plackett Burman was used to study the influence of input parameters on laccase yield. Tween-80, initial moisture ratio and magnesium sulphate were the major influencing factor affecting laccase yield. Central composite design of RSM was used for the modelling of experiment. Desirability approach was used to optimize laccase yield. Maximum laccase yield of 1645 IUg⁻¹ was obtained when 0.55% of tween -80, 1:2.34 initial moisture ratio and 300μM magnesium sulphate was used. A 470 fold increase in the yield of laccase from unoptimized condition was obtained.

A High Redox Potential Laccase from Pycnoporus sanguineus RP15: Potential Application for Dye Decolorization

Laccase production by Pycnoporus sanguineus RP15 grown in wheat bran and corncob under solid-state fermentation was optimized by response surface methodology using a Central Composite Rotational Design. A laccase (Lacps1) was purified and characterized and the potential of the pure Lacps1 and the crude culture extract for synthetic dye decolorization was evaluated. At optimal conditions (eight days, 26 °C, 18% (w/w) milled corncob, 0.8% (w/w) NH₄Cl and 50 mmol·L⁻¹ CuSO₄, initial moisture 4.1 mL·g⁻¹), the laccase activity reached 138.6 ± 13.2 U·g⁻¹. Lacps1 was a monomeric glycoprotein (67 kDa, 24% carbohydrate). Optimum pH and temperature for the oxidation of 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) were 4.4 and 74.4 °C, respectively. Lacps1 was stable at pH 3.0–8.0, and after two hours at 55–60 °C, presenting high redox potential (0.747 V vs. NHE). ABTS was oxidized with an apparent affinity constant of 147.0 ± 6.4 μmol·L⁻¹, maximum velocity of 413.4 ± 21.2 U·mg⁻¹ and catalytic efficiency of 3140.1 ± 149.6 L·mmol⁻¹·s⁻¹. The maximum decolorization percentages of bromophenol blue (BPB), remazol brilliant blue R and reactive blue 4 (RB4), at 25 or 40 °C without redox mediators, reached 90%, 80% and 60%, respectively, using either pure Lacps1 or the crude extract. This is the first study of the decolorization of BPB and RB4 by a P. sanguineus laccase. The data suggested good potential for treatment of industrial dye-containing effluents.

Extracellular laccase production and its optimization from Arthrospira maxima catalyzed decolorization of synthetic dyes

In the present study laccase production potential of a photosynthetic, non nitrogen fixing cyanobacteria Arthrospira maxima (SAE-25780) was investigated for their probable use in synthetic dye decolorization which poses environmental pollution problem in aquatic bodies. A. maxima (SAE-25780) showed a constitutive production of laccase which increased up to 80% in the presence of inducer guaiacol. The optimal condition for laccase was 30 °C, 10 mM sucrose as a carbon source, 10 mM sodium nitrate as a nitrogen source, and 2 mM copper as metal activator. The partially purified laccase showed 84% and 49% decolorization potential for the two anthroquinonic dyes-Reactive Blue 4 and Remazol Brilliant Blue R, respectively (RBBR) within 96 h without any mediator. Therefore the laccase extracted from A. maxima (SAE-25780) can be used efficiently in bioremediation of synthetic dyes from paper, pulp and textile industries.

Production of Extracellular Laccase from Bacillus subtilis MTCC 2414 Using Agroresidues as a Potential Substrate

Laccases are the model enzymes for multicopper oxidases and participate in several applications such as bioremediation, biopulping, textile, and food industries. Laccase producing bacterium, Bacillus subtilis MTCC 2414, was subjected to optimization by conventional techniques and was partially purified using ammonium salt precipitation method. The agroresidue substrates used for higher yield of laccase were rice bran and wheat bran. Maximum production was achieved at temperature 30°C (270 ± 2.78 U/mL), pH 7.0 (345 ± 3.14 U/mL), and 96 h (267 ± 2.64 U/mL) of incubation. The carbon and nitrogen sources resulted in high enzyme yield at 3% sucrose (275 ± 3.11 U/mL) and 3% peptone (352.2 ± 4.32 U/mL) for rice bran and 3% sucrose (247.4 ± 3.51 U/mL) and 3% peptone (328 ± 3.33 U/mL) for wheat bran, respectively. The molecular weights of partially purified laccase were 52 kDa for rice bran and 55 kDa for wheat bran. The laccase exhibited optimal activity at 70°C (260.3 ± 6.15 U/mL), pH 9.0 (266 ± 4.02 U/mL), and metal ion CuSO4 (141.4 ± 6.64) was found to increase the production. This is the first report that delivers the higher yield of laccase produced from B. subtilis MTCC 2414 using agroresidues as a potential substrate.

Production of Trametes pubescens laccase under submerged and semi-solid culture conditions on agro-industrial wastes

Laccases are copper-containing enzymes involved in the degradation of lignocellulosic materials and used in the treatment of phenol-containing wastewater. In this study we investigated the effect of culture conditions, i.e. submerged or semi-solid, and copper supplementation on laccase production by Trametespubescens grown on coffee husk, soybean pod husk, or cedar sawdust. The highest specific laccase activity was achieved when the culture was conducted under submerged conditions supplemented with copper (5 mM), and using coffee husk as substrate. The crude extracts presented two laccase isoforms with molecular mass of 120 (Lac1) and 60 kDa (Lac2). Regardless of the substrate, enzymatic crude extract and purified fractions behaved similarly at different temperatures and pHs, most of them presented the maximum activity at 55 °C and a pH range between 2 and 3. In addition, they showed similar stability and electro-chemical properties. At optimal culture conditions laccase activity was 7.69 ± 0.28 U mg(-1) of protein for the crude extract, and 0.08 ± 0.001 and 2.86 ± 0.05 U mg(-1) of protein for Lac1 and Lac2, respectively. In summary, these results show the potential of coffee husk as an important and economical growth medium to produce laccase, offering a new alternative use for this common agro-industrial byproduct.

A laccase with antiproliferative activity against tumor cells from an edible mushroom, white common Agrocybe cylindracea

A laccase, with HIV-1 reverse transcriptase inhibitory activity (IC(50)=12.7 μM) and antiproliferative activity against HepG2 cells (IC(50)=5.6 μM) and MCF7 cells (IC(50)=6.5 μM), was purified from fresh fruiting bodies of the edible white common Agrocybe cylindracea mushroom. The laccase, which had a novel N-terminal sequence, displayed a molecular mass of 58 kDa within the range reported for most other mushroom laccases. The purification protocol entailed ion exchange chromatography on DEAE-cellulose, SP-Sepharose, and Q-Sepharose and gel filtration on Superdex 75. The laccase was adsorbed on DEAE-cellulose and Q-Sepharose, but unadsorbed on SP-Sepharose. Its optimum pH was pH 3-4 and its optimum temperature was 50°C. The activity of the isolated laccase differed from one substrate to another. The ranking was ABTS>N,N-dimethyl-1,4-phenylenediamine>hydroquinone>catechol>2-methylcatechol>pyrogallol.

Use of experimental design for the optimization of the production of new secondary metabolites by two Penicillium species

A fractional factorial design approach has been used to enhance secondary metabolite production by two Penicillium strains. The method was initially used to improve the production of bioactive extracts as a whole and subsequently to optimize the production of particular bioactive metabolites. Enhancements of over 500% in secondary metabolite production were observed for both P. oxalicum and P. citrinum. Two new alkaloids, citrinalins A (5) and B (6), were isolated and identified from P. citrinum cultures optimized for production of minor metabolites.

Optimization of media components for laccase production by litter dwelling fungal isolate Fusarium incarnatum LD-3

Laccase production by solid state fermentation (SSF) using an indigenously isolated litter dwelling fungus Fusarium incarnatum LD-3 was optimized. Fourteen medium components were screened by the initial screening method of Plackett-Burman. Each of the components was screened on the basis of 'p' (probability value) which was above 95% confidence level. Ortho-dianisidine, thiamine HCl and CuSO(4) . 5 H(2)O were identified as significant components for laccase production. The Central Composite Design response surface methodology was then applied to further optimize the laccase production. The optimal concentration of these three medium components for higher laccase production were (g/l): CuSO(4) . 5 H(2)O, 0.01; thiamine HCl, 0.0136 and ortho-dianisidine, 0.388 mM served as an inducer. Wheat straw, 5.0 g was used as a solid substrate. Using this statistical optimization method the laccase production was found to increase from 40 U/g to 650 U/g of wheat straw, which was sixteen times higher than non optimized medium. This is the first report on statistical optimization of laccase production from Fusarium incarnatum LD-3.

Production and characterization of a novel laccase with cold adaptation and high thermal stability from an isolated fungus

A new white-rot fungus SYBC-L1, which could produce an extracellular laccase, was isolated from a decayed Elaeocarpus sylvestris. The strain was identified as Pycnoporus sp. SYBC-L1 according to the morphological characteristics and ribosomal ITS1-5.8S-ITS2 RNA genomic sequence analysis. The highest laccase activity of 24.1 U ml(-1), which was approximately 40-fold than that in basal medium, was achieved in optimal culture medium in submerged fermentation. The laccase produced by Pycnoporus sp. SYBC-L1 was not only a cold adaptation enzyme with a relative catalytic activity of 30.2% at 0 degrees C but also a high thermostable enzyme. The half-lives at 60, 70 and 80 degrees C were 85.5, 37.2, and 2.6 h, respectively. The laccase could effectively decolorize weak acid blue AS and diamond black PV up to 88% and 74.7%, respectively, within 2 h in the absence of any redox mediators. The results suggested Pycnoporus sp. SYBC-L1 was a potential candidate for laccase production and industrial application.