Purification, Biochemical Characterization, and Facile Immobilization of Laccase from Sphingobacterium ksn-11 and its Application in Transformation of Diclofenac

Optimization, purification and characterization of laccase from a new endophytic Trichoderma harzianum AUMC14897 isolated from Opuntia ficus-indica and its applications in dye decolorization and wastewater treatment

BACKGROUND

Hazardous synthetic dye wastes have become a growing threat to the environment and public health. Fungal enzymes are eco-friendly, compatible and cost-effective approach for diversity of applications. Therefore, this study aimed to screen, optimize fermentation conditions, and characterize laccase from fungal endophyte with elucidating its ability to decolorize several wastewater dyes.

RESULTS

A new fungal endophyte capable of laccase-producing was firstly isolated from cladodes of Opuntia ficus-indica and identified as T. harzianum AUMC14897 using ITS-rRNA sequencing analysis. Furthermore, the response surface methodology (RSM) was utilized to optimize several fermentation parameters that increase laccase production. The isolated laccase was purified to 13.79-fold. GFC, SDS-PAGE revealed laccase molecular weight at 72 kDa and zymogram analysis elucidated a single band without any isozymes. The peak activity of the pure laccase was detected at 50 °C, pH 4.5, with thermal stability up to 50 °C and half life span for 4 h even after 24 h retained 30% of its activity. The Km and Vmax values were 0.1 mM, 22.22 µmol/min and activation energy (Ea) equal to 5.71 kcal/mol. Furthermore, the purified laccase effectively decolorized various synthetic and real wastewater dyes.

CONCLUSION

Subsequently, the new endophytic strain produces high laccase activity that possesses a unique characteristic, it could be an appealing candidate for both environmental and industrial applications.

Optimizing laccase selection for enhanced outcomes: a comprehensive review

Despite their widespread applications in sectors such as pulp and paper, textile, food and beverage, pharmaceuticals, and biofuel production, laccases encounter challenges related to their activity and stability under varying reaction conditions. This review accumulates data on the complex interplay between laccase characteristics and reaction conditions for maximizing their efficacy in diverse biotechnological processes. Benefits of organic media such as improved substrate selectivity and reaction control, and their risks such as enzyme denaturation and reduced activity are reported. Additionally, the effect of reaction conditions such as pH and temperature on laccase activity and stability are gathered and reported. Sources like Bacillus pumilus, Alcaligenes faecalis, Bacillus clausii, and Bacillus tequilensis SN4 are producing laccases that are both thermo-active and alkali-active. Additionally, changes induced by the presence of various substances within reaction media such as metals, inhibitors, and organic solvents are also reported. Bacillus pumilus and Bacillus licheniformis LS04 produce the most resistant laccases in this case. Finally, the remarkable laccases have been highlighted and the proper laccase source for each industrial application is suggested.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-04015-5.

Harnessing the power of bacterial laccases for xenobiotic degradation in water: A 10-year overview

Industrialization and population growth are leading to the production of significant amounts of sewage containing hazardous xenobiotic compounds. These compounds pose a threat to human and animal health, as well as the overall ecosystem. To combat this issue, chemical, physical, and biological techniques have been used to remove these contaminants from water bodies affected by human activity. Biotechnological methods have proven effective in utilizing microorganisms and enzymes, particularly laccases, to address this problem. Laccases possess versatile enzymatic characteristics and have shown promise in degrading different xenobiotic compounds found in municipal, industrial, and medical wastewater. Both free enzymes and crude enzyme extracts have demonstrated success in the biotransformation of these compounds. Despite these advancements, the widespread use of laccases for bioremediation and wastewater treatment faces challenges due to the complex composition, high salt concentration, and extreme pH often present in contaminated media. These factors negatively impact protein stability, recovery, and recycling processes, hindering their large-scale application. These issues can be addressed by focusing on large-scale production, resolving operation problems, and utilizing cutting-edge genetic and protein engineering techniques. Additionally, finding novel sources of laccases, understanding their biochemical properties, enhancing their catalytic activity and thermostability, and improving their production processes are crucial steps towards overcoming these limitations. By doing so, enzyme-based biological degradation processes can be improved, resulting in more efficient removal of xenobiotics from water systems. This review summarizes the latest research on bacterial laccases over the past decade. It covers the advancements in identifying their structures, characterizing their biochemical properties, exploring their modes of action, and discovering their potential applications in the biotransformation and bioremediation of xenobiotic pollutants commonly present in water sources.

Removal and degradation of sodium diclofenac via radical-based mechanisms using S. sclerotiorum laccase

The recently isolated Sclerotinia sclerotiorum laccase was used for the degradation of sodium diclofenac, a nonsteroidal anti-inflammatory drug widely found in the aquatic environment. The Michaelis-Menten parameters, half-life of diclofenac at different pH values in presence of this enzyme and potential inhibitors were evaluated. Diclofenac-based radicals formed in presence of laccase were spin-trapped and detected using EPR spectroscopy. Almost complete diclofenac degradation (> 96%) occurred after a 30-h treatment via radical-based generated oligomers and their rapid precipitation, thus ensuring an unprecedented green formula suitable not only for degradation but also for straightforward removal of the degradation products. High performance liquid chromatography coupled with atmospheric pressure chemical ionization-ion trap mass spectrometry (HPLC-APCI-MS) analyses of the degradation products of diclofenac in aqueous dosage revealed the presence of at least seven products while HR Orbitrap MS analysis showed that the enzymatic treatment produced high molecular weight metabolites through a radical oligomerization mechanism of diclofenac. The enzymatically formed products precipitated and its constituting components were also characterized using UV-vis spectroscopy, infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA).

Heterologous expression, purification, and characterization of thermo- and alkali-tolerant laccase-like multicopper oxidase from Bacillus mojavensis TH309 and determination of its antibiotic removal potential

Laccases or laccase-like multicopper oxidases have great potential in bioremediation to oxidase phenolic or non-phenolic substrates. However, their inability to maintain stability in harsh environmental conditions and against non-substrate compounds is one of the main reasons for their limited use. The gene (mco) encoding multicopper oxidase from Bacillus mojavensis TH309 were cloned into pET14b( +), expressed in Escherichia coli, and purified as histidine tagged enzyme (BmLMCO). The molecular weight of the enzyme was about 60 kDa. The enzyme exhibited laccase-like activity toward 2,6-dimethoxyphenol (2,6-DMP), syringaldazine (SGZ), and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The highest enzyme activity was recorded at 80 °C and pH 8. BmLMCO showed a half-life of ~ 305, 99, 50, 46, 36, and 20 min at 40, 50, 60, 70, 80, and 90 °C, respectively. It retained more than 60% of its activity after pre-incubation in the range of pH 5-12 for 60 min. The enzyme activity significantly increased in the presence of 1 mM of Cu2+. Moreover, BmLMCO tolerated various chemicals and showed excellent compatibility with organic solvents. The Michaelis constant (Km) and the maximum velocity (Vmax) values of BmLMCO were 0.98 mM and 93.45 µmol/min, respectively, with 2,6-DMP as the substrate. BmLMCO reduced the antibacterial activity of cefprozil, gentamycin, and erythromycin by 72.3 ± 1.5%, 79.6 ± 6.4%, and 19.7 ± 4.1%, respectively. This is the first revealing shows the recombinant production of laccase-like multicopper oxidase from any B. mojavensis strains, its biochemical properties, and potential for use in bioremediation.

Applications and immobilization strategies of the copper-centred laccase enzyme; a review

Laccase is a multi-copper enzyme widely expressed in fungi, higher plants, and bacteria which facilitates the direct reduction of molecular oxygen to water (without hydrogen peroxide production) accompanied by the oxidation of an electron donor. Laccase has attracted attention in biotechnological applications due to its non-specificity and use of molecular oxygen as secondary substrate. This review discusses different applications of laccase in various sectors of food, paper and pulp, waste water treatment, pharmaceuticals, sensors, and fuel cells. Despite the many advantages of laccase, challenges such as high cost due to its non-reusability, instability in harsh environmental conditions, and proteolysis are often encountered in its application. One of the approaches used to minimize these challenges is immobilization. The various methods used to immobilize laccase and the different supports used are further extensively discussed in this review.

Green remediation potential of immobilized oxidoreductases to treat halo-organic pollutants persist in wastewater and soil matrices - A way forward

The alarming presence of hazardous halo-organic pollutants in wastewater and soils generated by industrial growth, pharmaceutical and agricultural activities is a major environmental concern that has drawn the attention of scientists. Unfortunately, the application of conventional technologies within hazardous materials remediation processes has radically failed due to their high cost and ineffectiveness. Consequently, the design of innovative and sustainable techniques to remove halo-organic contaminants from wastewater and soils is crucial. Altogether, these aspects have led to the search for safe and efficient alternatives for the treatment of contaminated matrices. In fact, over the last decades, the efficacy of immobilized oxidoreductases has been explored to achieve the removal of halo-organic pollutants from diverse tainted media. Several reports have indicated that these enzymatic constructs possess unique properties, such as high removal rates, improved stability, and excellent reusability, making them promising candidates for green remediation processes. Hence, in this current review, we present an insight of green remediation approaches based on the use of immobilized constructs of phenoloxidases (e.g., laccase and tyrosinase) and peroxidases (e.g., horseradish peroxidase, chloroperoxidase, and manganese peroxidase) for sustainable decontamination of wastewater and soil matrices from halo-organic pollutants, including 2,4-dichlorophenol, 4-chlorophenol, diclofenac, 2-chlorophenol, 2,4,6-trichlorophenol, among others.

Marine sediment derived bacteria Enterobacter asburiae ES1 and Enterobacter sp. Kamsi produce laccase with high dephenolisation potentials

Purified laccases from bacterial species isolated from marine sediment were applied to degrade Bisphenol A (BPA). The Bacterial species were isolated from marine water sediments sampled from Cove Rock and Bonza Bay beach of the Eastern Cape Province, South Africa was tested for laccase activity on varied phenolic plates. The two most promising strains, Enterobacter asburiae ES1 and Enterobacter sp. Kamsi was subjected to extracellular laccase production and were identified using molecular methods. Both extracted bacterial laccases showed an affinity for ABTS and PFC substrates and were purified to homogeneity by ammonium sulfate precipitation, anion exchange, and size exclusion chromatography. A specific laccase activity of 231.67 and 218.15 U/mg of protein and a molecular weight of 50 and 55 kDa was obtained from the purified ES1 and Kamsi laccases. Laccase activity was optimum at pH8 and 5 and at 80 °C and 60 °C for ES1 and Kamsi laccases, and they manifested 71.7% and 65.8% BPA decolorizing effects. The optimized treatment condition applied showed maximum BPA removal effects of 85% and 86% at pH7 and 6, while 78% and 79% was degraded at 70 °C and 80 °C while at 250 µL enzyme volume, BPA was actively degraded to 85%, and 75% removal effect showed by ES1 and Kamsi laccases. The molecular identification of the pure colonies using 16S rRNA showed the isolate belonged to the class of gammaproteobacterial. Their nucleotide sequence has been deposited in NCBI with the accession number MN686602 and MN686603. Conclusively, marine habitat serves as a reservoir for active bacterial laccase producers suitable for bioprocess application.