Green biocatalyst for decolorization of azo dyes from industrial wastewater: Coriolopsis trogii 2SMKN laccase immobilized on recycled brewer's spent grain.

This study presents an innovative approach for the reuse and recycling of waste material, brewer's spent grain (BSG) for creating a novel green biocatalyst. The same BSG was utilized in several consecutive steps: initially, it served as a substrate for the cultivation and production of laccase by a novel isolated fungal strain, Coriolopsis trogii 2SMKN, then, it was reused as a carrier for laccase immobilization, aiding in the process of azo dye decolorization and finally, reused as recycled BSG for the second successful laccase immobilization for six guaiacol oxidation, contributing to a zero-waste strategy. The novel fungal strain produced laccase with a maximum activity of 171.4 U/g after 6 days of solid-state fermentation using BSG as a substrate. The obtained laccase exhibited excellent performance in the decolorization of azo dyes, both as a free and immobilized, at high temperatures, without addition of harmful mediators, achieving maximum decolorization efficiencies of 99.0%, 71.2%, and 61.0% for Orange G (OG), Congo Red, and Eriochrome Black T (EBT), respectively. The immobilized laccase on BSG was successfully reused across five cycles of azo dye decolorization process. Notably, new green biocatalyst outperformed commercial laccase from Aspergillus spp. in the decolorization of OG and EBT. GC-MS and LC-MS revealed azo-dye degradation products and decomposition pathway. This analysis was complemented by antimicrobial and phytotoxicity tests, which confirmed the non-toxic nature of the degradation products, indicating the potential for safe environmental disposal.

Bioremediation of 2,4,6-trichlorophenol by extracellular enzymes of white rot fungi immobilized with sodium alginate/hydroxyapatite/chitosan microspheres.

Hydroxyapatite, a calcium phosphate biomass material known for its excellent biocompatibility, holds promising applications in water, soil, and air treatment. Sodium alginate/hydroxyapatite/chitosan (SA-HA-CS) microspheres were synthesized by cross-linking sodium alginate with calcium chloride. These microspheres were carriers for immobilizing extracellular crude enzymes from white rot fungi through adsorption, facilitating the degradation of 2,4,6-trichlorophenol (2,4,6-TCP) in water and soil. At 50 °C, the immobilized enzyme retained 87.2% of its maximum activity, while the free enzyme activity dropped to 68.86%. Furthermore, the immobilized enzyme maintained 68.09% of its maximum activity at pH 7, surpassing the 51.16% observed for the free enzyme. Under optimal conditions (pH 5, 24 h), the immobilized enzymes demonstrated a remarkable 94.7% removal rate for 160 mg/L 2,4,6-TCP, outperforming the 62.1% achieved by free crude enzymes. The degradation of 2,4,6-TCP by immobilized and free enzymes adhered to quasi-first-order degradation kinetics. Based on LC-MS, the plausible biodegradation mechanism and reaction pathway of 2,4,6-TCP were proposed, with the primary degradation product identified as 1,2,4-trihydroxybenzene. The immobilized enzyme effectively removed 72.9% of 2,4,6-TCP from the soil within 24 h. The degradation efficiency of the immobilized enzyme varied among different soil types, exhibiting a negative correlation with soil organic matter content. These findings offer valuable insights for advancing the application of immobilized extracellular crude enzymes in 2,4,6-TCP remediation.

A novel laccase from Trametes polyzona with high performance in the decolorization of textile dyes.

Laccases are multicopper oxidases able to oxidize several phenolic compounds and find application in numerous industrial applications. Among laccase producers, white-rot fungi represent a valuable source of multiple isoforms and isoenzymes of these multicopper oxidases. Here we describe the identification, biochemical characterization, and application of laccase 2 from Trametes polyzona (TP-Lac2), a basidiomycete fungus emerged among others that have been screened by plate assay. This enzyme has an optimal temperature of 50 °C and in acidic conditions it is able to oxidize both phenolic and non-phenolic compounds. The ability of TP-Lac2 to decolorize textile dyes was tested in the presence of natural and synthetic mediators at 30 °C and 50 °C. Our results indicate that TP-Lac2 most efficiently decolorizes (decolorization rate > 75%) malachite green oxalate, orange G, amido black10B and bromocresol purple in the presence of acetosyringone and 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonate)-ABTS. Overall, the laccase mediator system consisting of TP-Lac2 and the natural mediator acetosyringone has potential as an environmentally friendly alternative for wastewater treatment in the textile industry.

Study on the degradation conditions of corn stalks by Asian corn borer digestive enzymes combined with white-rot fungus.

Since the environmentally friendly reuse of corn stalks attracts more and more attention, it is an efficient and feasible way to reuse corn stalks as forage. However, whether the cellulose, lignin, and hemicellulose within corn stalks can be effectively decomposed becomes a key to reusing corn stalks as forage. Orthogonal test was designed by five different degradation temperatures (22°C, 24°C, 26°C, 28°C, 30°C), five different pH values (4, 5, 6, 8, 10), and five different degradation time durations (5, 15, 25, 30, and 35 days) to examine 25 kinds of different degradation conditions. It was found that the decomposition effect of hemicellulose, cellulose, and lignin, of group 25 (26°C, pH = 5, 25 days) was stronger compared with other groups, with the contents calculated as 8.22%, 31.55%, and 22.55% individually (p < 0.01, p < 0.05). Group 19 (22°C, pH = 4, 5 days) revealed the worst degradation effect of cellulose, lignin, and hemicellulose compared to other groups, with contents calculated as 15.48%, 38.85%, and 29.57%, individually (p < 0.01, p < 0.05). The research data deliver a basis for ideal degradation conditions for corn stalks degradation in combination with the digestive enzymes of P. chrysosporium and O. furnacalis larva. Aiming to explore a highly efficient and environmentally friendly corn stalk degradation method.

White Rot Fungi as Tools for the Bioremediation of Xenobiotics: A Review.

Industrial development has enhanced the release into the environment of large quantities of chemical compounds with high toxicity and limited prospects of degradation. The pollution of soil and water with xenobiotic chemicals has become a major ecological issue; therefore, innovative treatment technologies need to be explored. Fungal bioremediation is a promising technology exploiting their metabolic potential to remove or lower the concentrations of xenobiotics. In particular, white rot fungi (WRF) are unique microorganisms that show high capacities to degrade a wide range of toxic xenobiotic compounds such as synthetic dyes, chlorophenols, polychlorinated biphenyls, organophosphate pesticides, explosives and polycyclic aromatic hydrocarbons (PAHs). In this review, we address the main classes of enzymes involved in the fungal degradation of organic pollutants, the main mechanisms used by fungi to degrade these chemicals and the suitability of fungal biomass or extracellular enzymes for bioremediation. We also exemplify the role of several fungi in degrading pollutants such as synthetic dyes, PAHs and emerging pollutants such as pharmaceuticals and perfluoroalkyl/polyfluoroalkyl substances (PFASs). Finally, we discuss the existing current limitations of using WRF for the bioremediation of polluted environments and future strategies to improve biodegradation processes.

Optimized decolorization of two poly azo dyes Sirius Red and Sirius Blue using laccase-mediator system.

Factors, namely pH, laccase-like activity, dyes concentration as well as 1-Hydroxybenzotriazole (HBT) concentration was examined. The results indicated that the maximum decolorization yield and rate reached 98.30 ± 0.10% and 5.84 ± 0.01%/min, respectively for Sirius Blue, and 99.34 ± 0.47% and 5.85 ± 0.12%/min, respectively for Sirius Red after 4 h. The presence of the redox mediator 1-hydroxybenzotriazole (HBT) greatly improved the decolorization levels. The optimum concentrations of HBT, dyes, and laccase were 0.62 mM, 50 mg/L, and 0.89 U/mL respectively at pH 4.58 for both dyes. Phytotoxicity tests using treated and untreated dyes proved that the applied treatment slightly decreased the toxicity of the by-products. However, the germination index (GI) increased from 14.6 to 36.08% and from 31.6 to 36.96% for Sirius Red and Sirius Blue, respectively. The present study focused on the treatment of two recalcitrant azo dyes, namely: Sirius Blue (Direct Blue 71) and Sirius Red (Direct Red 80). The decolorization was performed using cell-free supernatant from Coriolopsis gallica culture with high laccase activity. Response surface methodology (RSM) and Box-Behnken design were applied to optimize the decolorization of the two tested dyes. The effect of four.

Efficiency of thermostable purified laccase isolated from Physisporinus vitreus for azo dyes decolorization.

Laccases are versatile biocatalysts that are prominent for industrial purposes due to their extensive substrate specificity. Therefore, this research investigated producing laccase from Physisporinus vitreus via liquid fermentation. The results revealed that veratryl alcohol (4mM) was the most effective inducer 7500U/L. On the other hand, Zn ions inhibited laccase production. The optimum carbon and nitrogen sources were glucose and tryptone by 5200 and 3300 U/L, respectively. Moreover, solvents exhibited various impacts on the enzyme activity at three different solvent concentrations (5%, 10% and 20%), however, it showed a highest activity at 5% of the investigated solvent. Ferric ions inhibited the enzyme activity. In addition, the enzyme has a high ability to decolorize azo dyes when using syringaldehyde as a mediator. The purified laccase from Physisporinus vitreus is a promising substance to be used for industrial and environmental applications due to its stability under harsh conditions and efficiency in decolorization of dyes.

Biologically active secondary metabolites from white-rot fungi.

In recent years, there has been a considerable rise in the production of novel metabolites derived from fungi compared to the ones originating from bacteria. These organic substances are utilized in various sectors such as farming, healthcare, and pharmaceutical. Since all dividing living cells contain primary metabolites, secondary metabolites are synthesized by utilizing intermediate compounds or by-products generated from the primary metabolic pathways. Secondary metabolites are not critical for the growth and development of an organism; however, they exhibit a variety of distinct biological characteristics. White-rot fungi are the only microorganisms able to decompose all wood components. Hence, they play an important role in both the carbon and nitrogen cycles by decomposing non-living organic substrates. They are ubiquitous in nature, particularly in hardwood (e.g., birch and aspen) forests. White-rot fungi, besides ligninolytic enzymes, produce different bioactive substances during their secondary metabolism including some compounds with antimicrobial and anticancer properties. Such properties could be of potential interest for the pharmaceutical industries. Considering the importance of the untapped biologically active secondary metabolites from white-rot fungi, the present paper reviews the secondary metabolites produced by white-rot fungi with different interesting bioactivities.

Effective Decolorization and Detoxification of Single and Mixed Dyes with Crude Laccase Preparation from a White-Rot Fungus Strain Pleurotus eryngii.

To fully harness the potential of laccase in the efficient decolorization and detoxification of single and mixed dyes with diverse chemical structures, we carried out a systematic study on the decolorization and detoxification of single and mixed dyes using a crude laccase preparation obtained from a white-rot fungus strain, Pleurotus eryngii. The crude laccase preparation showed efficient decolorization of azo, anthraquinone, triphenylmethane, and indigo dyes, and the reaction rate constants followed the order Remazol Brilliant Blue R > Bromophenol blue > Indigo carmine > New Coccine > Reactive Blue 4 > Reactive Black 5 > Acid Orange 7 > Methyl green. This laccase preparation exhibited notable tolerance to SO42- salts such as MnSO4, MgSO4, ZnSO4, Na2SO4, K2SO4, and CdSO4 during the decolorization of various types of dyes, but was significantly inhibited by Cl- salts. Additionally, this laccase preparation demonstrated strong tolerance to some organic solvents such as glycerol, ethylene glycol, propanediol, and butanediol. The crude laccase preparation demonstrated the efficient decolorization of dye mixtures, including azo + azo, azo + anthraquinone, azo + triphenylmethane, anthraquinone + indigo, anthraquinone + triphenylmethane, and indigo + triphenylmethane dyes. The decolorization kinetics of mixed dyes provided preliminary insight into the interactions between dyes in the decolorization process of mixed dyes, and the underlying reasons and mechanisms were discussed. Importantly, the crude laccase from Pleurotus eryngii showed efficient repeated-batch decolorization of single-, two-, and four-dye mixtures. This crude laccase demonstrated high stability and reusability in repeated-batch decolorization. Furthermore, this crude laccase was efficient in the detoxification of different types of single dyes and mixed dyes containing different types of dyes, and the phytotoxicity of decolorized dyes (single and mixed dyes) was significantly reduced. The crude laccase efficiently eliminated phytotoxicity associated with single and mixed dyes. Consequently, the crude laccase from Pleurotus eryngii offers significant potential for practical applications in the efficient decolorization and management of single and mixed dye pollutants with different chemical structures.

Harnessing the potential of white rot fungi and ligninolytic enzymes for efficient textile dye degradation: A comprehensive review.

The contamination of wastewater with textile dyes has emerged as a pressing environmental concern due to its persistent nature and harmful effects on ecosystems. Conventional dye treatment methods have proven inadequate in effectively breaking down complex dye molecules. However, a promising alternative for textile dye degradation lies in the utilization of white rot fungi, renowned for their remarkable lignin-degrading capabilities. This review provides a comprehensive analysis of the potential of white rot fungi in degrading textile dyes, with a particular focus on their ligninolytic enzymes, specifically examining the roles of lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase in the degradation of lignin and their applications in textile dye degradation. The primary objective of this paper is to elucidate the enzymatic mechanisms involved in dye degradation, with a spotlight on recent research advancements in this field. Additionally, the review explores factors influencing enzyme production, including culture conditions and genetic engineering approaches. The challenges associated with implementing white rot fungi and their ligninolytic enzymes in textile dye degradation processes are also thoroughly examined. Textile dye contamination poses a significant environmental threat due to its resistance to conventional treatment methods. White rot fungi, known for their ligninolytic capabilities, offer an innovative approach to address this issue. The review delves into the intricate mechanisms through which white rot fungi and their enzymes, including LiP, MnP, and laccase, break down complex dye molecules. These enzymes play a pivotal role in lignin degradation, a process that can be adapted for textile dye removal. The review also emphasizes recent developments in this field, shedding light on the latest findings and innovations. It discusses how culture conditions and genetic engineering techniques can influence the production of these crucial enzymes, potentially enhancing their efficiency in textile dye degradation. This highlights the potential for tailored enzyme production to address specific dye contaminants effectively. The paper also confronts the challenges associated with integrating white rot fungi and their ligninolytic enzymes into practical textile dye degradation processes. These challenges encompass issues like scalability, cost-effectiveness, and regulatory hurdles. By acknowledging these obstacles, the review aims to pave the way for practical and sustainable applications of white rot fungi in wastewater treatment. In conclusion, this comprehensive review offers valuable insights into how white rot fungi and their ligninolytic enzymes can provide a sustainable solution to the urgent problem of textile dye-contaminated wastewater. It underscores the enzymatic mechanisms at play, recent research breakthroughs, and the potential of genetic engineering to optimize enzyme production. By addressing the challenges of implementation, this review contributes to the ongoing efforts to mitigate the environmental impact of textile dye pollution. PRACTITIONER POINTS: Ligninolytic enzymes from white rot fungi, like LiP, MnP, and laccase, are crucial for degrading textile dyes. Different dyes and enzymatic mechanisms is vital for effective wastewater treatment. Combine white rot fungi-based strategies with mediator systems, co-culturing, or sequential treatment approaches to enhance overall degradation efficiency. Emphasize the broader environmental impact of textile dye pollution and position white rot fungi as a promising avenue for contributing to mitigation efforts. This aligns with the overarching goal of sustainable wastewater treatment practices and environmental conservation. Consider scalability, cost-effectiveness, and regulatory compliance to pave the way for sustainable applications that can effectively mitigate the environmental impact of textile dye pollution.

Copper removal from aqueous solutions by white rot fungus Pleurotus ostreatus GEMB-PO1 and its potential in co-remediation of copper and organic pollutants.

Addressing the environmental contamination from heavy metals and organic pollutants remains a critical challenge. This study explored the resilience and removal potential of Pleurotus ostreatus GEMB-PO1 for copper. P. ostreatus GEMB-PO1 showed significant tolerance, withstanding copper concentrations up to 2 mM. Its copper removal efficiency ranged from 64.56 % at 0.5 mM to 22.90 % at 8 mM. Transcriptomic insights into its response to copper revealed a marked upregulation in xenobiotic degradation-related enzymes, such as laccase and type II peroxidases. Building on these findings, a co-remediation system using P. ostreatus GEMB-PO1 was developed to remove both copper and organic pollutants. While this approach significantly enhanced the degradation efficiency of organic contaminants, it concurrently exhibited a diminished efficacy in copper removal within the composite system. This study underscores the potential of P. ostreatus GEMB-PO1 in environmental remediation. Nevertheless, further investigation is required to optimize the simultaneous removal of organic pollutants and copper.

Copper increases laccase gene transcription and extracellular laccase activity in Pleurotus eryngii KS004.

The white-rot fungus Pleurotus eryngii secretes various laccases involved in the degradation of a wide range of chemical compounds. Since the laccase production is relatively low in fungi, many efforts have been focused on finding ways to increase it, so in this study, we investigated the effect of copper on the transcription of the pel3 laccase gene and extracellular laccase activity. The results indicate that adding 0.5 to 2 mM copper to liquid cultures of P. eryngii KS004 increased both pel3 gene transcription and extracellular laccase activity in a concentration-dependent manner. The most significant increase in enzyme activity occurred at 1 mM Cu2+, where the peak activity was 4.6 times higher than in control flasks. Copper also induced the transcription of the laccase gene pel3. The addition of 1.5 and 2 mM Cu2+ to fungal culture media elevated pel3 transcript levels to more than 13-fold, although the rate of induction slowed down at Cu2+ concentrations higher than 1.5 mM. Our findings suggest that copper acts as an inducer in the regulation of laccase gene expression in P. eryngii KS004. Despite its inhibitory effect on fungal growth, supplementing cultures with copper can lead to an increased extracellular laccase production in P. eryngii.

A review on the management of rinse wastewater in the agricultural sector.

Pesticides have become indispensable compounds to sustain global food production. However, a series of sustainable agricultural practices must be ensured to minimize health and environmental risks, such as eco-friendly cultivation techniques, the transition to biopesticides, appropriate hygiene measures, etc. Hygiene measures should include the management of rinse wastewater (RWW) produced when cleaning agricultural equipment and machinery contaminated with pesticides (among other pollutants), such as sprayers or containers. Although some technical guidelines encourage the reuse of RWW in agricultural fields, in many cases the application of specialized treatments is a more environmentally friendly option. Solar photocatalysis was found to be the most widely studied physical-chemical method, especially in regions with intense solar radiation, generally using catalysts such as TiO2, Na2S2O8, and H2O2, operating for relatively short treatment periods (usually from 10 min to 9 h) and requiring accumulated radiation levels typically ranging from 3000 to 10000 kJ m-2. Biological treatments seem to be particularly suitable for this application. Among them, biobed is a well-established and robust technology for the treatment of pesticide-concentrated water in some countries, with operating periods that typically range from 1 to 24 months, and with temperatures preferably close to 20 °C; but further research is required for its implementation in other regions and/or conditions. Solar photocatalysis and biobeds are the only two systems that have been tested in full-scale treatments. Alternatively, fungal bioremediation using white rot fungi has shown excellent efficiencies in the degradation of pesticides from agricultural wastewater. However, greater efforts should be invested in gathering more information to consolidate these technologies and expand their use in the agricultural sector.

Induction of Extracellular Hydroxyl Radicals Production in the White-Rot Fungus Pleurotus eryngii for Dyes Degradation: An Advanced Bio-oxidation Process.

Among pollution remediation technologies, advanced oxidation processes (AOPs) are genuinely efficient since they are based on the production of strong, non-selective oxidants, mainly hydroxyl radicals (·OH), by a set of physicochemical methods. The biological counterparts of AOPs, which may be referred to as advanced bio-oxidation processes (ABOPs), have begun to be investigated since the mechanisms of induction of ·OH production in fungi are known. To contribute to the development of ABOPs, advanced oxidation of a wide number of dyes by the white-rot fungus Pleurotus eryngii, via a quinone redox cycling (QRC) process based on Fenton's reagent formation, has been described for the first time. The fungus was incubated with 2,6-dimethoxy-1,4-benzoquinone (DBQ) and Fe3+-oxalate, with and without Mn2+, leading to different ·OH production rates, around twice higher with Mn2+. Thanks to this process, the degradative capacity of the fungus increased, not only oxidising dyes it was not otherwise able to, but also increasing the decolorization rate of 20 dyes by more than 7 times in Mn2+ incubations. In terms of process efficacy, it is noteworthy that with Mn2+ the degradation of the dyes reached values of 90-100% in 2-4 h, which are like those described in some AOPs based on the Fenton reaction.

Lignin-degrading enzyme production was enhanced by the novel transcription factor Ptf6 in synergistic microbial co-culture.

Synergistic microbial co-culture has been an efficient and energy-saving strategy to produce lignin-degrading enzymes (LDEs), including laccase, manganese peroxidase, and versatile peroxidase. However, the regulatory mechanism of microbial co-culture is still unclear. Herein, the extracellular LDE activities of four white-rot fungi were significantly increased by 88-544% over monoculture levels when co-cultured with Rhodotorula mucilaginosa. Ptf6 was demonstrated from the 9 million Y1H clone library to be a shared GATA transcription factor in the four fungi, and could directly bind to the laccase gene promoter. Ptf6 exists in two alternatively spliced isoforms under monoculture, namely Ptf6-α (1078 amino acids) containing Cys2/Cys2-type zinc finger and Ptf6-ß (963 amino acids) lacking the complete domain. Ptf6 responded to co-culture by up-regulation of both its own transcripts and the proportion of Ptf6-α. Ptf6-α positively activated the production of most LDE isoenzymes and bound to four GATA motifs on the LDEs' promoter with different affinities. Moreover, Ptf6-regulation mechanism can be applicable to a variety of microbial co-culture systems. This study lays a theoretical foundation for further improving LDEs production and providing an efficient way to enhance the effects of biological and enzymatic pretreatment for lignocellulosic biomass conversion.

Combining fungal bioremediation and ozonation for rinse wastewater treatment.

In this work, agricultural rinse wastewater, which is produced during the cleaning of agricultural equipment and constitutes a major source of pesticides, was treated by fungal bioremediation and ozonation, both individually and combined in a two-stage treatment train. Three major pesticides (thiacloprid, chlortoluron, and pyrimethanil) were detected in rinse wastewater, with a total concentration of 38.47 mg C L-1. Comparing both technologies, ozonation in a stirred reactor achieved complete removal of these pesticides (720 min) while proving to be a more effective approach for reducing colour, organic matter, and bacteria. However, this technique produced transformation products and increased toxicity. In contrast, fungal bioremediation in a rotating drum bioreactor attenuated toxicity levels and did not produce such metabolites, but only removed approximately 50 % of target pesticide - hydraulic retention time (HRT) of 5 days - and obtained worse results for most of the general quality parameters studied. This work also includes a preliminary economic assessment of both technologies, revealing that fungal bioremediation was 2 times more cost-effective than ozonation. The treatment train, consisting of a first stage of fungal bioremediation followed by ozonation, was found to be a promising approach as it synergistically combines the advantages of both treatments, achieving high removals of pesticides (up to 100 %) and transformation products, while reducing operating costs and producing a biodegradable effluent. This is the first time that fungal bioremediation and ozonation technologies have been compared and combined in a treatment train to deal with pesticides in agricultural rinse wastewater.

Solid-State Fermentation with White Rot Fungi (Pleurotus Species) Improves the Chemical Composition of Highland Barley Straw as a Ruminant Feed and Enhances In Vitro Rumen Digestibility.

Lignin degradation is important for enhancing the digestibility and improving the nutritive quality of ruminant feeds. White rot fungi are well known for their bioconversion of lignocellulosic biomass. The objective of this paper was to evaluate whether Lentinus sajor-caju, Pleurotus ostreatus, Phyllotopsis rhodophylla, Pleurotus djamor, Pleurotus eryngii, and Pleurotus citrinopileatus treatments altered the chemical compositions of highland barley straw constituents and enhanced their nutritional value as a ruminant feed. All white rot fungi significantly increased the relative crude protein (CP), ethyl ether extract (EE), starch, soluble protein (SP), and non-protein nitrogen (NPN) contents but decreased the ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and acid detergent insoluble protein (ADFIP) contents. In addition, L. sajor-caju treatment increased (p < 0.001) the levels of PA, PB2, PB3, CA, CB1, CB2, and CNSC, but reduced (p < 0.001) the PC and CC in the solid-state fermentation of highland barley straw. Maximum ligninlysis (50.19%) was optimally produced in the presence of 1.53% glucose and 2.29% urea at 22.72 ℃. The in vitro dry matter digestibility and total volatile fatty acid concentrations of fermented highland barley straw, as well as the fermentability, were optimized and improved with L. sajor-caju, which degraded the lignocellulose and improved the nutritional value of highland barley straw as a ruminant feed.

Effect of feeding Pleurotus pulmonarius-treated empty fruit bunch on nutrient digestibility and milk fatty acid profiles in goats.

This study aimed to evaluate the effect of feeding P. pulmonarius-treated empty fruit bunch (FTEFB) on the nutrient intakes, digestibility, milk yield and milk profiles of lactating Saanen goats. A total of nine lactating Saanen goats were used in an incomplete cross-over experimental design. The balanced dietary treatments contain different replacement levels of Napier grass with FTEFB at 0% (0-FT), 25% (25-FT) and 50% (50-FT). The FTEFB contained crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) at 4.10, 94.6, 70.8 and 19.4% DM, respectively. The replacement of FTEFB in 25-FT did not alter dry matter, NDF, hemicellulose, ADL, ether extract and gross energy intakes when compared to the control fed group (0-FT). The ADF and cellulose intake was higher in 25-FT than in the others (P < 0.001). The digestibility of hemicellulose, cellulose and ADL were not changed in 25-FT compared to the control group (P < 0.05) whereas when 50% FTEFB was incorporated to the diet, intermediate digestibility was decreased significantly (P < 0.05). Milk yield and protein content did not differ between the goat received 25-FT and the control group (P > 0.05). There are no differences in milk fatty profiles between dietary treatments (P > 0.05), except for OCFA. Goat fed with 25-FT had the lowest OCFA (P < 0.01) and significantly reduced the lauric acid concentration (P < 0 .05) when compared to the control group. Thus, replacement of NG in 25-FT does not adversely affect nutrient intake, fibre digestibility (cellulose and hemicellulose), milk yield, milk composition and milk fatty acid profiles. Overall, FTEFB may have potential to be used in the dairy goat diet as a roughage source to replace Napier grass.

Characterization of white rot fungi from wood decayed for lignin degradation.

The present study was conducted to isolate and identify white rot fungi (WRF) from wood decayed and to determine their ability to produce lignin-modifying enzymes (LMEs), specifically laccase (Lac), lignin peroxidase (LiP), and manganese peroxidase (MnP), on solid and liquid media supplemented with synthetic dyes namely 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), azure B, and phenol red. A total of 23 isolates of WRF were isolated from decayed wood and identified as eight different species namely Phanerochaete australis, Perenniporia tephropora, Lentinus squarrosulus, Ganoderma australe, Trametes polyzona, Lentinus sajor-caju, Gymnopilus dilepis, and Fomitopsis palustris based on morphological characteristics, DNA sequences of the internal transcribed spacer (ITS) region, and phylogenetic inference. The fungal isolates can be divided into four groups based on the type of LMEs produced, namely A (Lac-LiP-MnP) with 16 isolates, B (Lac-MnP) (three isolates), C (Lac) (three isolates), and D (MnP) (one isolate). This study highlights P. australis (BJ38) as the best producer of Lac and LiP, while L. squarrosulus (IPS72) is the best producer of MnP. The present study is the first reported P. australis as an efficient lignin degrader by demonstrating the highest activity of two important LMEs.

Growth inhibition and tissue accumulation of palladium in the ubiquitous macrofungus Pleurotus ostreatus (oyster mushroom).

The growth effects and tissue accumulation of palladium (Pd) in the ubiquitous white-rot macrofungus Pleurotus ostreatus (oyster mushroom) are reported. Submerged cultures of P. ostreatus were exposed to Pd (as Na2PdCl4) at concentrations of 0, 6.25, 12.5, 25, 50 and 100 mg/L in potato dextrose broth media and incubated for 18 days at 25 °C. The growth response was measured as dried tissue biomass. Relative to controls, growth was partially inhibited at [Pd]broth = 25 and 50 mg/L. The minimum inhibitory concentration (MIC) of Pd was 100 mg Pd/L. Mean Pd concentrations of dry tissue (± standard error) ranged from 93.5 ± 17.1 mg Pd/kg to 1912.0 ± 293.9 mg Pd/kg, with bioconcentration factors (BCFs) ranging from 16.10 ± 4.17 to 40.91 ± 8.89. A linear positive log-log relationship was found between the Ctissue and [Pd]broth (R2 = 0.476), consistent with a Freundlich isotherm model of sorption. This relationship suggested that physicochemical processes may dominate tissue Pd accumulation in this system rather than biological processes.