Production of laccase and xylanase from Coriolus versicolor grown on tomato pomace and their chromatographic behaviour on immobilized metal chelates

Unlocking the potential of Algerian lignocellulosic biomass: exploring indigenous microbial diversity for enhanced enzyme and sugar production

Nowadays, natural resources like lignocellulosic biomass are gaining more and more attention. This study was conducted to analyse chemical composition of dried and ground samples (500 μm) of various Algerian bioresources including alfa stems (AS), dry palms (DP), olive pomace (OP), pinecones (PC), and tomato waste (TW). AS exhibited the lowest lignin content (3.60 ± 0.60%), but the highest cellulose (58.30 ± 2.06%), and hemicellulose (20.00 ± 3.07%) levels. DP, OP, and PC had around 30% cellulose, and 10% hemicellulose. OP had the highest lignin content (29.00 ± 6.40%), while TW contained (15.70 ± 2.67% cellulose, 13.70 ± 0.002% hemicellulose, and 17.90 ± 4.00% lignin). Among 91 isolated microorganisms, nine were selected for cellulase, xylanase, and/or laccase production. The ability of Bacillus mojavensis to produce laccase and cellulase, as well as B. safensis to produce cellulase and xylanase, is being reported for the first time. In submerged conditions, TW was the most suitable substrate for enzyme production. In this conditions, T. versicolor K1 was the only strain able to produce laccase (4,170 ± 556 U/L). Additionally, Coniocheata hoffmannii P4 exhibited the highest cellulase activity (907.62 ± 26.22 U/L), and B. mojavensis Y3 the highest xylanase activity (612.73 ± 12.73 U/L). T. versicolor K1 culture showed reducing sugars accumulation of 18.87% compared to initial concentrations. Sucrose was the predominant sugar detected by HPLC analysis (13.44 ± 0.02 g/L). Our findings suggest that T. versicolor K1 holds promise for laccase production, while TW represents a suitable substrate for sucrose production.

Yellow laccase produced by Trametes versicolor K1 on tomato waste: A comparative study with the blue one produced on semi-synthetic medium

Laccase production by fungal growth on agrifood waste is still poorly studied. Trametes versicolor K1 isolated from palm bark produced a yellow non glycosylated laccase from tomato waste based medium (TMT) and a blue glycosylated laccase on glucose medium (GLU). Lignocellulosic biomass, such as pinecones (PIN), palm leaves (PLM), olive pomace (OLV), and alfa stems (ALF) have also been used as growth medium for T. versicolor K1. In these conditions, very low or no laccase production was observed. When peptone was supplied in TMT medium, the laccase activity increased from 4170 U/L to 8618 U/L. By increasing the culture volume up to 1 L, laccase production on TMT was 9929 U/L. The yellow laccase (TmtLac) was purified from the supernatant TMT medium and has shown similar characteristics with the blue laccase (GluLac) purified from the GLU medium. Their apparent protein size was 63 kDa. Catalytic activities of the yellow form were not very different from those of the blue form, but specific activity of the purified yellow laccase produced on tomato waste was much higher. The K_m and V_m values for four substrates, ABTS, DMP, guaiacol, and pyrogallol were almost similar for both isoenzymes. The optimum pH and temperature were respectively 4.0 and 50 °C. Although the level of glycosylation is clearly different, the thermostability of TmtLac and GluLac are quite similar. TmtLac is even slightly more tolerant at 60 °C for 24 h than GluLac. Moreover TmtLac showed greater stability at alkaline pH after 24 h compared to that of GluLac.We demonstrate that activity of the yellow TmtLac is not significantly affected compared to the blue laccase and that tomato waste is a simple and interesting lignocellulosic substrate to the laccase producer Trametes sp.

Improved performance of immobilized laccase for catalytic degradation of synthetic dyes using redox mediators

Laccase is an important biodegradation agent as the catalytic degradation could be enhanced in the presence of redox mediators. This work aims to improve removal performance of the immobilized laccase...

Screening of Novel Laccase Producers-Isolation and Characterization of Cold-Adapted Laccase from Kabatiella bupleuri G3 Capable of Synthetic Dye Decolorization

Psychrophilic laccases catalyzing the bond formation in mild, environmentally friendly conditions are one of the biocatalysts at the focus of green chemistry. Screening of 41 cold-adapted strains of yeast and yeast-like fungi revealed a new laccase-producing strain, which was identified as Kabatiella bupleuri G3 IBMiP according to the morphological characteristics and analysis of sequences of the D1/D2 regions of 26S rDNA domain and the ITS1-5,8S-ITS2 region. The extracellular activity of laccase in reaction with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) at the optimal pH 3.5 was 215 U/L after 15 days of growth in a medium with waste material and 126 U/L after 25 days of cultivation in a defined medium. Copper (II) ions (0.4 mM), Tween 80 (1.0 mM) and ascorbic acid (5.0 mM) increased the production of laccase. The optimum temperature for enzyme operation is in the range of 30-40 °C and retains over 60% of the maximum activity at 10 °C. New laccase shows high thermolability-half-life at 40 °C was only 60 min. Enzyme degradation of synthetic dyes was the highest for crystal violet, i.e., 48.6% after 1-h reaction with ABTS as a mediator. Outcomes of this study present the K. bupleuri laccase as a potential psychrozyme for environmental and industrial applications.

Improved performance of immobilized laccase on Fe3O4@C-Cu2+ nanoparticles and its application for biodegradation of dyes

An effective strategy for enhancement of catalytic activity and stability of immobilized laccase via metal affinity adsorption on Fe₃O₄@C-Cu²⁺ nanoparticles was developed, which involved the fabrication of hydroxyl and carboxyl functionalized Fe₃O₄@C nanoparticles via a simple hydrothermal process and the subsequent chelation with Cu²⁺ for the immobilization of laccase under a mild condition. Our results revealed that the Fe₃O₄@C-Cu²⁺ nanoparticles possess a high loading amount of bovine serum albumin (BSA, 436 mg/g support) and laccase activity recovery of 82.3 % after immobilization. Laccase activity assays indicated that thermal and pH stabilities, and resistances to organic solvents and metal ions of the immobilized laccase were relatively higher than those of the free enzyme. The immobilized laccase maintained more than 61 % of its original activity after 10 consecutive reuses. Most importantly, the immobilized laccase possessed excellent degradation of diverse synthetic dyes. The degradation rates of malachite green (MG), brilliant green (BG), crystal violet (CV), azophloxine, Procion red MX-5B, and reactive blue 19 (RB19) was approximately 99, 93, 79, 88, 75 and 81 (%) in the first cycle. Even after 10 consecutive reuses, the removal efficiencies of the six dyes were found to be 94, 80, 71, 78, 60, and 65 (%), respectively.

Fruit and Vegetable Waste: Bioactive Compounds, Their Extraction, and Possible Utilization

Fruits and vegetables are the most utilized commodities among all horticultural crops. They are consumed raw, minimally processed, as well as processed, due to their nutrients and health-promoting compounds. With the growing population and changing diet habits, the production and processing of horticultural crops, especially fruits and vegetables, have increased very significantly to fulfill the increasing demands. Significant losses and waste in the fresh and processing industries are becoming a serious nutritional, economical, and environmental problem. For example, the United Nations Food and Agriculture Organization (FAO) has estimated that losses and waste in fruits and vegetables are the highest among all types of foods, and may reach up to 60%. The processing operations of fruits and vegetables produce significant wastes of by-products, which constitute about 25% to 30% of a whole commodity group. The waste is composed mainly of seed, skin, rind, and pomace, containing good sources of potentially valuable bioactive compounds, such as carotenoids, polyphenols, dietary fibers, vitamins, enzymes, and oils, among others. These phytochemicals can be utilized in different industries including the food industry, for the development of functional or enriched foods, the health industry for medicines and pharmaceuticals, and the textile industry, among others. The use of waste for the production of various crucial bioactive components is an important step toward sustainable development. This review describes the types and nature of the waste that originates from fruits and vegetables, the bioactive components in the waste, their extraction techniques, and the potential utilization of the obtained bioactive compounds.

Purification and immobilization of laccase from Trichoderma harzianum strain HZN10 and its application in dye decolorization

In this study we report the purification of laccase produced by Trichoderma harzianum strain HZN10 (using wheat bran under solid state fermentation) and its application in decolorization of synthetic dyes. Extracellular laccase was purified to homogeneity by DEAE-Sepharose and Sephadex G-100 chromatography with specific activity of 162.5 U/mg and 25-fold purification. Purified laccase was immobilized in various entrapments like calcium alginate, copper alginate, calcium alginate-chitosan beads and sol-gel matrix. Optimization results revealed that the laccase immobilized in sol-gel was optimally active in wide pH range (4.0-7.0) and thermo-stable (50-70 °C) than free enzyme which was optimum at 50 °C and pH 6.0. Kinetic analysis showed K m of 0.5 mM and 2.0 mM and V max of 285 U/mg and 500 U/mg by free laccase and sol-gel immobilized laccase respectively with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) [ABTS] substrate. Free and immobilized laccase was employed for decolorization of three different synthetic dyes (malachite green, methylene blue and congo red). High performance liquid chromatography (HPLC) analysis results revealed that approximately 100% of malachite green, 90% of methylene blue and 60% of congo red dyes at initial concentration of 200 mg/L were decolorized within 16, 18 and 20 h, respectively by laccase immobilized in sol-gel matrix in the presence of 1-hydroxybenzotriazole (HBT) mediator. During the decolorization all three synthetic dyes showed various peaks on HPLC chromatogram indicating different by-products formation. Finally, phytotoxicity analysis results revealed that the by-products of synthetic dyes (formed during decolorization) showed less toxicity against Phaseolus mungo compared to untreated synthetic dyes.

Production of Enzymes From Agricultural Wastes and Their Potential Industrial Applications

Enzymatic hydrolysis is the significant technique for the conversion of agricultural wastes into valuable products. Agroindustrial wastes such as rice bran, wheat bran, wheat straw, sugarcane bagasse, and corncob are cheapest and plentifully available natural carbon sources for the production of industrially important enzymes. Innumerable enzymes that have numerous applications in industrial processes for food, drug, textile, and dye use have been produced from different types of microorganisms from agricultural wastes. Utilization of agricultural wastes offers great potential for reducing the production cost and increasing the use of enzymes for industrial purposes. This chapter focuses on economic production of actinobacterial enzymes from agricultural wastes to make a better alternative for utilization of biomass generated in million tons as waste annually.

Overexpression of a novel thermostable and chloride-tolerant laccase from Thermus thermophilus SG0.5JP17-16 in Pichia pastoris and its application in synthetic dye decolorization

Laccases have been used for the decolorization and detoxification of synthetic dyes due to their ability to oxidize a wide variety of dyes with water as the sole byproduct. A putative laccase gene (LacTT) from Thermus thermophilus SG0.5JP17-16 was screened using the genome mining approach, and it was highly expressed in Pichia pastoris, yielding a high laccase activity of 6130 U/L in a 10-L fermentor. The LacTT open reading frame encoded a protein of 466 amino acid residues with four putative Cu-binding regions. The optimal pH of the recombinant LacTT was 4.5, 6.0, 7.5 and 8.0 with 2,2'-azino-bis(3-ethylbenzothazoline-6-sulfonic acid) (ABTS), syringaldazine (SGZ), guaiacol, and 2,6-dimethoxyphenol (2,6-DMP) as the substrate, respectively. The optimal temperature of LacTT was 90°C with guaiacol as the substrate. LacTT was highly stable at pH 4.0-11.0 and thermostable at 40°C-90°C, confirming that it is a pH-stable and thermostable laccase. Furthermore, LacTT also exhibited high tolerance to halides such as NaCl, NaBr and NaF, and decolorized 100%, 94%, 94% and 73% of Congo Red, Reactive Black B and Reactive Black WNN, and Remazol Brilliant Blue R, respectively. Interestingly, addition of high concentration of NaCl increased the RBBR decolorization efficiency of LacTT. These results suggest that LacTT is a good candidate for industrial applications such as dyestuff processing and degradation of dyes in textile wastewaters.

High impact biowastes from South European agro-industries as feedstock for second-generation biorefineries

Availability of bio-based chemicals, materials and energy at reasonable cost will be one of the forthcoming issues for the EU economy. In particular, the development of technologies making use of alternative resources to fossil fuels is encouraged by the current European research and innovation strategy to face the societal challenge of natural resource scarcity, fossil resource dependence and sustainable economic growth. In this respect, second- generation biorefineries, i.e. biorefineries fed with biowastes, appear to be good candidates to substitute and replace the present downstream processing scheme. Contrary to first-generation biorefineries, which make use of dedicated crops or primary cultivations to achieve such a goal, the former employ agricultural, industrial, zootechnical, fishery and forestry biowastes as the main feedstock. This leaves aside any ethical and social issue generated by first-generation approaches, and concomitantly prevents environmental and economical issues associated with the disposal of the aforementioned leftovers. Unfortunately, to date, a comprehensive and updated mapping of the availability and potential use of bioresources for second-generation biorefineries in Europe is missing. This is a lack that severely limits R&D and industrial applications in the sector. On the other hand, attempts at valorizing the most diverse biowastes dates back to the nineteenth century and plenty of information in the literature on their sustainable exploitation is available. However, the large majority of these investigations have been focused on single fractions of biowastes or single steps of biowaste processing, preventing considerations on an integrated and modular (cascade) approach for the whole valorization of organic leftovers. This review aims at addressing these issues by gathering recent data on (a) some of the main high-impact biowastes located in Europe and in particular in its Southern part, and (b) the bio-based chemicals, materials and fuels that can be produced from such residues. In particular, we focused on those key compounds referred to as "chemical platforms", which have been indicated as fundamental to generate the large majority of the industrially relevant goods to date.

LacSubPred: predicting subtypes of Laccases, an important lignin metabolism-related enzyme class, using in silico approaches

Background

Laccases (E.C. 1.10.3.2) are multi-copper oxidases that have gained importance in many industries such as biofuels, pulp production, textile dye bleaching, bioremediation, and food production. Their usefulness stems from the ability to act on a diverse range of phenolic compounds such as o-/p-quinols, aminophenols, polyphenols, polyamines, aryl diamines, and aromatic thiols. Despite acting on a wide range of compounds as a family, individual Laccases often exhibit distinctive and varied substrate ranges. This is likely due to Laccases involvement in many metabolic roles across diverse taxa. Classification systems for multi-copper oxidases have been developed using multiple sequence alignments, however, these systems seem to largely follow species taxonomy rather than substrate ranges, enzyme properties, or specific function. It has been suggested that the roles and substrates of various Laccases are related to their optimal pH. This is consistent with the observation that fungal Laccases usually prefer acidic conditions, whereas plant and bacterial Laccases prefer basic conditions. Based on these observations, we hypothesize that a descriptor-based unsupervised learning system could generate homology independent classification system for better describing the functional properties of Laccases.

Results

In this study, we first utilized unsupervised learning approach to develop a novel homology independent Laccase classification system. From the descriptors considered, physicochemical properties showed the best performance. Physicochemical properties divided the Laccases into twelve subtypes. Analysis of the clusters using a t-test revealed that the majority of the physicochemical descriptors had statistically significant differences between the classes. Feature selection identified the most important features as negatively charges residues, the peptide isoelectric point, and acidic or amidic residues. Secondly, to allow for classification of new Laccases, a supervised learning system was developed from the clusters. The models showed high performance with an overall accuracy of 99.03%, error of 0.49%, MCC of 0.9367, precision of 94.20%, sensitivity of 94.20%, and specificity of 99.47% in a 5-fold cross-validation test. In an independent test, our models still provide a high accuracy of 97.98%, error rate of 1.02%, MCC of 0.8678, precision of 87.88%, sensitivity of 87.88% and specificity of 98.90%.

Conclusion

This study provides a useful classification system for better understanding of Laccases from their physicochemical properties perspective. We also developed a publically available web tool for the characterization of Laccase protein sequences (http://lacsubpred.bioinfo.ucr.edu/). Finally, the programs used in the study are made available for researchers interested in applying the system to other enzyme classes (https://github.com/tweirick/SubClPred).

Functionalized magnetic mesoporous silica nanoparticles: fabrication, laccase adsorption performance and direct laccase capture from Trametes versicolor fermentation broth

A simple and highly efficient protocol using magnetic mesoporous silica nanoparticles (MMSNPs) with metal affinity ligands was developed to directly capture laccase from Trametes versicolor fermentation broth. The Cu(2+)-chelated magnetic mesoporous silica nanoparticles (MMSNPs-Cu(2+)) with pore sizes ranging from 3.6 to 27.1 nm exhibited size selectivity on laccase capture from the fermentation broth, and the MMSNPs-Cu(2+) with an average pore size of 14.5 nm provided 60.6-fold purification of laccase and 114.6% recovery yield of enzyme activity. Both size selectivity of the MMSNPs and affinity of the chelated metal ion resulted in high laccase capture efficiency from the fermentation broth. The most efficient MMSNPs-Cu(2+) demonstrated no significant loss in laccase capture effectiveness following 10 reuse cycles. This simple and efficient strategy has the potential to be used for the robust and inexpensive preparation of purified laccase at the industrial scale.

A chloride tolerant laccase from the plant pathogen ascomycete Botrytis aclada expressed at high levels in Pichia pastoris

Fungal laccases from basidiomycetous fungi are thoroughly investigated in respect of catalytic mechanism and industrial applications, but the number of reported and well characterized ascomycetous laccases is much smaller although they exhibit interesting catalytic properties. We report on a highly chloride tolerant laccase produced by the plant pathogen ascomycete Botrytis aclada, which was recombinantly expressed in Pichia pastoris with an extremely high yield and purified to homogeneity. In a fed-batch fermentation, 495 mg L(-1) of laccase was measured in the medium, which is the highest concentration obtained for a laccase by a yeast expression system. The recombinant B. aclada laccase has a typical molecular mass of 61,565 Da for the amino acid chain. The pI is approximately 2.4, a very low value for a laccase. Glycosyl residues attached to the recombinant protein make up for approximately 27% of the total protein mass. B. aclada laccase exhibits very low K(M) values and high substrate turnover numbers for phenolic and non-phenolic substrates at acidic and near neutral pH. The enzyme's stability increases in the presence of chloride ions and, even more important, its substrate turnover is only weakly inhibited by chloride ions (I(50)=1.4M), which is in sharp contrast to most other described laccases. This high chloride tolerance is mandatory for some applications such as implantable biofuel cells and laccase catalyzed reactions, which suffer from the presence of chloride ions. The high expression yield permits fast and easy production for further basic and applied research.

Immobilized laccase on a new cryogel carrier and kinetics of two anthraquinone derivatives oxidation

A coordinatively immobilized laccase was prepared using a new cryogel type carrier. The support has a wide-pore texture facilitating diffusion of different substrates to the enzyme reaction center. The biocatalyst proved to be efficient in decolorization of two anthraquinone derivatives, namely Acid Blue 62 and bromaminic acid. After 24 h over 80% of the two substrates have been oxidated. The kinetic data (K (m) and V (max)) for the oxidation of the two anthraquinone derivatives, with the free and immobilized enzyme, have been determined and compared. Other parameters, like k (cat) and the specificity constant have been calculated and analyzed. The influence of substrate properties (hydrophobicity, polarity, etc.) has been discussed.

Chromatographic behaviour of monoclonal antibodies against wild-type amidase from Pseudomonas aeruginosa on immobilized metal chelates

The aim of this work was to devise a one-step purification procedure for monoclonal antibodies (MAbs) of IgG class by immobilized metal affinity chromatography (IMAC). Therefore, several stationary phases were prepared containing immobilized metal chelates in order to study the chromatographic behaviour of MAbs against wild-type amidase from Pseudomonas aeruginosa. Such MAbs adsorbed to Cu(II), Ni(II), Zn(II) and Co(II)-IDA agarose columns. The increase in ligand concentration and the use of longer spacer arms and higher pH values resulted in higher adsorption of MAbs into immobilized metal chelates. The dynamic binding capacity and the maximum binding capacity were 1.33 ± 0.015 and 3.214 ± 0.021 mg IgG/mL of sedimented commercial matrix, respectively. A K(D) of 4.53 × 10(-7) m was obtained from batch isotherm measurements. The combination of tailor-made stationary phases of IMAC and the correct selection of adsorption conditions permitted a one-step purification procedure to be devised for MAbs of IgG class. Culture supernatants containing MAbs were purified by IMAC on commercial-Zn(II) and EPI-30-IDA-Zn(II) Sepharose 6B columns and by affinity chromatography on Protein A-Sepharose CL-4B. This MAb preparation revealed on SDS-PAGE two protein bands with M(r) of 50 and 22 kDa corresponding to the heavy and light chains, respectively.

Magnetic mesoporous silica nanoparticles: fabrication and their laccase immobilization performance

Newly large-pore magnetic mesoporous silica nanoparticles (MMSNPs) with wormhole framework structures were synthesized for the first time by using tetraethyl orthosilicate as the silica source and amine-terminated Jeffamine surfactants as template. Iminodiacerate was attached on these MMSNPs through a silane-coupling agent and chelated with Cu(2+). The Cu(2+)-chelated MMSNPs (MMSNPs-CPTS-IDA-Cu(2+)) showed higher adsorption capacity of 98.1 mg g(-1)-particles and activity recovery of 92.5% for laccase via metal affinity adsorption in comparison with MMSNPs via physical adsorption. The Michaelis constant (K(m)) and catalytic constant (k(cat)) of laccase immobilized on the MMSNPs-CPTS-IDA-Cu(2+) were 3.28 mM and 155.4 min(-1), respectively. Storage stability and temperature endurance of the immobilized laccase on MMSNPs-CPTS-IDA-Cu(2+) increased significantly, and the immobilized laccase retained 86.6% of its initial activity after 10 successive batch reactions operated with magnetic separation.