Neopestalotiopsis species presenting wide dye destaining activity: report of a mycelium-associated laccase

Systematic screening strategy for fungal laccase activity of endophytes from Otoba gracilipes with bioremediation potential

Fungal laccases are promising for biotechnological applications, including bioremediation and dye biotransformation, due to their high redox potential and broad substrate specificity. However, current bioprospecting methods for identifying laccase-producing fungi can be challenging and time-consuming. For early detection, it was developed a three-step, multi-criteria weighting system that evaluates fungal strains based on: First, the biotransformation capacity of three dyes (i.e., Congo red, brilliant blue G-250, and malachite green), at three different pH values, and with a relative weighting supported for the redox potential of each colorant. The relative decolorization coefficient (RDC), used as th2e first classification criterion, expressed their potential performance. Second, under the same conditions, laccase activity was estimated by observing the different degrees of oxidation of a given substrate. The selection criterion was the relative oxidation coefficient (ROC). Finally, laccase activity was quantified in submerged fermentations using three inducers (i.e., loofah sponge, Tween 80, and veratyl alcohol). This multicriteria screening strategy evaluated sixteen isolated endophytic fungal strains from Otoba gracilipes. The system identified Beltraniopsis sp. ET-17 (at pH values of 5.00 and 5.50) as a promising strain for dye biotransformation, and Phlebia floridensis as the best laccase producer, achieving a high activity of 116 μmol min-1 L-1 with loofah sponge as an inducer. In-vitro testing confirmed the efficacy of P. floridensis, with 53.61 % decolorization of a dye mixture (brilliant blue-Congo red. ratio 1:1) after 15 days of incubation. Thus, with the proposed screening strategy it was possible to highlight two species of interest at an early bioprospecting stage on a Colombian native tree poorly explored.

Impact of textile dyes on health and ecosystem: a review of structure, causes, and potential solutions

The rapid growth of population and industrialization have intensified the problem of water pollution globally. To meet the challenge of industrialization, the use of synthetic dyes in the textile industry, dyeing and printing industry, tannery and paint industry, paper and pulp industry, cosmetic and food industry, dye manufacturing industry, and pharmaceutical industry has increased exponentially. Among these industries, the textile industry is prominent for the water pollution due to the hefty consumption of water and discharge of coloring materials in the effluent. The discharge of this effluent into the aquatic reservoir affects its biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), and pH. The release of the effluents without any remedial treatment will generate a gigantic peril to the aquatic ecosystem and human health. The ecological-friendly treatment of the dye-containing wastewater to minimize the detrimental effect on human health and the environment is the need of the hour. The purpose of this review is to evaluate the catastrophic effects of textile dyes on human health and the environment. This review provides a comprehensive insight into the dyes and chemicals used in the textile industry, focusing on the typical treatment processes for their removal from industrial wastewaters, including chemical, biological, physical, and hybrid techniques.

Plant associated endophytic fungi as potential bio-factories for extracellular enzymes: Progress, Challenges and Strain improvement with precision approaches

There is an intricate network of relations between endophytic fungi and their hosts that affects the production of various bioactive compounds. Plant-associated endophytic contain industrially important enzymes and have the potential to fulfill their rapid demand in the international market to boost business in technology. Being safe and metabolically active, they have replaced the usage of toxic and harmful chemicals and hold a credible application in biotransformation, bioremediation, and industrial processes. Despite these, there are limited reports on fungal endophytes that can directly cater to the demand and supply of industrially stable enzymes. The underlying reasons include low endogenous production and secretion of enzymes from fungal endophytes which have raised concern for widely accepted applications. Hence it is imperative to augment the biosynthetic and secretory potential of fungal endophytes. Modern state-of-the-art biotechnological technologies aiming at strain improvement using cell factory engineering as well as precise gene editing like Clustered Regularly Interspaced Palindromic Repeats (CRISPR) and its Associated proteins (Cas) systems which can provide a boost in fungal endophyte enzyme production. Additionally, it is vital to characterize optimum conditions to grow one strain with multiple enzymes (OSME). The present review encompasses various plants-derived endophytic fungal enzymes and their applications in various sectors. Further, we postulate the feasibility of new precision approaches with an aim for strain improvement and enhanced enzyme production.

High dye removal capacity of Peniophora laxitexta immobilized in a combined support based on polyurethane foam and lignocellulosic substrates

Dye removal from effluents is a major problem for most textile industries. At present, wastewater treatments are currently based on physico-chemical methods which are expensive, energy inefficient and of limited versatility. The aim of this work was to find a low-cost and efficient method for dye removal. To do this, we designed a combined system based on the immobilization of the ligninolytic white-rot fungus Peniophora laxitexta (BAFC 4687) on mixed supports consisting of two polyurethane foam discs and a middle layer of diverse lignocellulosic substrates: soybean hulls, wheat straw or cellulose spent casings. As a corticioid fungus, P. laxitexta was able to completely colonize the supports developing a compact and tight structure that maintained the integrity of the system after several dye removal cycles. The immobilized fungus removed between 30% and 50% of the azoic dye Xylidine and more than 50% of the anthraquinonic dye RBBR in three successive cycles, and near 90% of the triphenylmethane Malachite Green in 10 repeated cycles without any loss of efficiency. Our analysis showed that the removal of the dyes was due to the combined effect of adsorption to the supports and enzymatic decolorization by soluble laccases and enzymes associated with the mycelium. Additionally, we showed that the presence of Malachite Green induced the expression of a new laccase isoform with high decolorization capacity. Based on these results, we propose that this inoculated laminar biocarrier could be effectively used for dye removal in textile wastewater.

Biotransformation ability of endophytic fungi: from species evolution to industrial applications

Abstract

Increased understanding of the interactions between endophytic fungi and plants has led to the discovery of a new generation of chemical compounds and processes between endophytic fungi and plants. Due to the long-term co-evolution between fungal endophytes and host plants, endophytes have evolved special biotransformation abilities, which can have critical consequences on plant metabolic processes and their composition. Biotransformation or bioconversion can impact the synthesis and decomposition of hormones, sugars, amino acids, vitamins, lipids, proteins, and various secondary metabolites, including flavonoids, polysaccharides, and terpenes. Endophytic fungi produce enzymes and various bioactive secondary metabolites with industrial value and can degrade or sequester inorganic and organic small molecules and macromolecules (e.g., toxins, pollutants, heavy metals). These fungi also have the ability to cause highly selective catalytic conversion of high-value compounds in an environmentally friendly manner, which can be important for the production/innovation of bioactive molecules, food and nutrition, agriculture, and environment. This work mainly summarized recent research progress in this field, providing a reference for further research and application of fungal endophytes.

Key points

•The industrial value of degradation of endophytes was summarized.

• The commercial value for the pharmaceutical industry is reviewed.

Graphical abstract

Augmented Biodegradation of Textile Azo Dye Effluents by Plant Endophytes: A Sustainable, Eco-Friendly Alternative

Textile industry consumes a large proportion of available water and releases huge amounts of toxic azo dye effluents, leading to an inevitable situation of acute environmental pollution that has been a significant threat to mankind. Decolorization or detoxification of harmful azo dyes has become a global priority to overcome the disastrous consequences and salvage the ecosystem. Biodegradation of textile azo dyes by endophytes stands to be a lucrative and viable alternative over conventional physico-chemical methods, owing to their eco-friendliness, cost-competitive and non-toxic nature. Especially, plant endophytic microbes exhibit promising biodegradation potential which has wired up the effective removal of textile azo dyes, attributing to their ability to produce dye degrading enzymes, laccases, peroxidases and azoreductases. Although both bacterial and fungal endophytes have been tried for azo dye degradation, endophytic fungi find broader application over bacteria. Despite of the advancements made in microbe-mediated biodegradation, there is still a need to fill the gap in lab to in situ translation of biodegradation research. This review concisely accentuates the xenobiotics of textile azo dyes and microbial mechanisms of biodegradation of textile azo dyes, positing plant endophytic community, especially bacterial and fungal endophytes as the potential dye degraders, highlighting currently reported dye degrading endophytic species.

Unveiling of Concealed Processes for the Degradation of Pharmaceutical Compounds by Neopestalotiopsis sp

The presence of pharmaceutical products has raised emerging biorisks in aquatic environments. Fungi have been considered in sustainable approaches for the degradation of pharmaceutical compounds from aquatic environments. Soft rot fungi of the Ascomycota phylum are the most widely distributed among fungi, but their ability to biodegrade pharmaceuticals has not been studied as much as that of white rot fungi of the Basidiomycota phylum. Herein, we evaluated the capacity of the soft rot fungus Neopestalotiopsis sp. B2B to degrade pharmaceuticals under treatment of woody and nonwoody lignocellulosic biomasses. Nonwoody rice straw induced laccase activity fivefold compared with that in YSM medium containing polysaccharide. But B2B preferentially degraded polysaccharide over lignin regions in woody sources, leading to high concentrations of sugar. Hence, intermediate products from saccharification may inhibit laccase activity and thereby halt the biodegradation of pharmaceutical compounds. These results provide fundamental insights into the unique characteristics of pharmaceutical degradation by soft rot fungus Neopestalotiopsis sp. in the presence of preferred substrates during delignification.