Variable protein expression in marine-derived filamentous fungus Penicillium chrysogenum in response to varying copper concentrations and salinity

Evaluation of copper-tolerant fungi isolated from Sarcheshmeh copper mine of Iran

Mycoremediation, a subset of bioremediation, is considered an advanced method to eliminate environmental contaminations. To identify tolerant fungi to copper contamination and study the related gene expression, sampling was carried out from the soil of "Sarcheshmeh Copper Mine," which is one of the biggest open-cast copper mines in the world. A total of 71 fungal isolates were obtained and purified. Afterward, the inhibitory effect of different concentrations (1000, 1500, 3500, 4000, and 5500 ppm) of copper sulfate on mycelial growth was evaluated. Results indicated that only 5500 ppm of copper sulfate inhibited fungal growth compared to the control. Based on the bioassay experiments, three isolates including S3-1, S3-21, and S1-7, which were able to grow on solid and broth medium containing 5500 ppm of copper sulfate at different pH conditions, were selected and identified using molecular approaches. Also, laccase and metallothionein gene expression has been assessed in these isolates. According to the molecular identification using ITS1-5.8S- ITS2 region, isolates S3-1 and S1-7 were identified as Pleurotus eryngii, and isolate S3-21 belonged to the genus Sarocladium. In addition, P. eryngii showed laccase gene expression reduction after 8 days of exposure to copper sulfate. While in the genus Sarocladium, it increased (almost 2 times) from 6 to 8 days. Besides, metallothionein gene expression has increased from 6 to 8 days of copper sulfate treatment compared to the control which reveals its role in copper tolerance of all studied isolates. In this study, Pleurotus eryngii and Sarocladium sp. are introduced as heavy metal tolerant fungi and the related gene expression to copper tolerance was studied for the first time in Iran.

Copper-Contaminated Substrate Biosorption by Penicillium sp. Isolated from Kefir Grains

In this bioremediation study, the fungus Penicillium sp. isolated from kefir grains was evaluated for its resistance to copper in the culture medium. Penicillium sp. was cultivated in liquid medium prepared using 2% malt-agar at pH 7.0. Biomass of the fungus was significantly reduced, but only when 800 mg·L^-1 of Cu(NO₃)₂ copper nitrate was used. The effect on radial growth of the fungus in experiments combining different pH values and the inorganic contaminant showed an inhibition of 73% at pH 4.0, 75% at pH 7.0 and 77% at pH 9.0 in liquid medium. Thus, even though the growth of Penicillium sp. could be inhibited with relatively high doses of copper nitrate, images obtained with scanning electron microscopy showed the preservation of fungal cell integrity. Therefore, it can be concluded that Penicillium sp. isolated from kefir grains can survive while performing bioremediation to minimize the negative effects of copper on the environment through biosorption.

Acetylcholine Esterase Inhibitory Effect, Antimicrobial, Antioxidant, Metabolomic Profiling, and an In Silico Study of Non-Polar Extract of The Halotolerant Marine Fungus Penicillium chrysogenum MZ945518

Major health issues, such as the rise in oxidative stress, incidences of Alzheimer’s disease, and infections caused by antibiotic-resistant microbes, have prompted researchers to look for new therapeutics. Microbial extracts are still a good source of novel compounds for biotechnological use. The objective of the current work was to investigate marine fungal bioactive compounds with potential antibacterial, antioxidant, and acetylcholinesterase inhibitory effects. Penicillium chrysogenum strain MZ945518 was isolated from the Mediterranean Sea in Egypt. The fungus was halotolerant with a salt tolerance index of 1.3. The mycelial extract showed antifungal properties against Fusarium solani with an inhibitory percentage of 77.5 ± 0.3, followed by Rhizoctonia solani and Fusarium oxysporum with percentages of 52 ± 0.0 and 40 ± 0.5, respectively. The extract also showed antibacterial activity against both Gram-negative and Gram-positive bacterial strains using the agar diffusion technique. The fungal extract was significantly more effective with Proteus mirabilis ATCC 29906 and Micrococcus luteus ATCC 9341; inhibition zones recorded 20 and 12 mm, respectively, compared with the antibiotic gentamycin, which recorded 12 and 10 mm, respectively. The antioxidant activity of the fungus extract revealed that it successfully scavenged DPPH free radicals and recorded an IC50 of 542.5 µg/mL. Additionally, it was capable of reducing Fe3+ to Fe2+ and exhibiting chelating ability in the metal ion-chelating test. The fungal extract was identified as a crucial inhibitor of acetylcholinesterase with an inhibition percentage of 63% and an IC50 value of 60.87 µg/mL. Using gas chromatography–mass spectrometry (GC/MS), 20 metabolites were detected. The most prevalent ones were (Z)-18-octadec-9-enolide and 1,2-Benzenedicarboxylic acid, with ratios of 36.28 and 26.73%, respectively. An in silico study using molecular docking demonstrated interactions between the major metabolites and the target proteins, including: DNA Gyrase, glutathione S-transferase, and Acetylcholinesterase, confirming the extract’s antimicrobial and antioxidant activity. Penicillium chrysogenum MZ945518, a halotolerant strain, has promising bioactive compounds with antibacterial, antioxidant, and acetylcholinesterase inhibitory activities

Insight Into the Molecular Mechanisms Underpinning the Mycoremediation of Multiple Metals by Proteomic Technique

We investigated the fungus Aspergillus fumigatus PD-18 responses when subjected to the multimetal combination (Total Cr, Cd2+, Cu2+, Ni2+, Pb2+, and Zn2+) in synthetic composite media. To understand how multimetal stress impacts fungal cells at the molecular level, the cellular response of A. fumigatus PD-18 to 30 mg/L multimetal stress (5 mg/L of each heavy metal) was determined by proteomics. The comparative fungal proteomics displayed the remarkable inherent intracellular and extracellular mechanism of metal resistance and tolerance potential of A. fumigatus PD-18. This study reported 2,238 proteins of which 434 proteins were exclusively expressed in multimetal extracts. The most predominant functional class expressed was for cellular processing and signaling. The type of proteins and the number of proteins that were upregulated due to various stress tolerance mechanisms were post-translational modification, protein turnover, and chaperones (42); translation, ribosomal structure, and biogenesis (60); and intracellular trafficking, secretion, and vesicular transport (18). In addition, free radical scavenging antioxidant proteins, such as superoxide dismutase, were upregulated upto 3.45-fold and transporter systems, such as protein transport (SEC31), upto 3.31-fold to combat the oxidative stress caused by the multiple metals. Also, protein–protein interaction network analysis revealed that cytochrome c oxidase and 60S ribosomal protein played key roles to detoxify the multimetal. To the best of our knowledge, this study of A. fumigatus PD-18 provides valuable insights toward the growing research in comprehending the metal microbe interactions in the presence of multimetal. This will facilitate in development of novel molecular markers for contaminant bioremediation.

The Presence of Marine Filamentous Fungi on a Copper-Based Antifouling Paint

Marine biofouling is undesirable growth on submerged substances, which causes a major problem for maritime industries. Antifouling paints containing toxic compounds such as copper are used to prevent marine biofouling. However, bacteria and diatoms are usually found in biofilms developed on such paints. In this study, plastic panels painted with a copper-based self-polishing antifouling paint were exposed to biofouling for 6 months in the Marina Bandar Rowdha, Sea of Oman. Clean panels were used as a control substratum. Marine filamentous fungi from protected and unprotected substrate were isolated on a potato dextrose agar. Pure isolates were identified using sequences of the ITS region of rDNA. Six fungal isolates (Alternaria sp., Aspergillus niger, A. terreus, A. tubingensis, Cladosporium halotolerans, and C. omanense) were obtained from the antifouling paint. Four isolates (Aspergillus pseudodeflectus, C. omanense, and Parengyodontium album) were isolated from clean panels and nylon ropes. This is the first evidence of the presence of marine fungi on antifouling paints. In comparison with isolates from the unprotected substrate, fungi from the antifouling paint were highly resistant to copper, which suggests that filamentous fungi can grow on marine antifouling paints.

Bioremediation mechanism and potential of copper by actively growing fungus Trichoderma lixii CR700 isolated from electroplating wastewater

Present study investigated the Cu²⁺ removal potential of Trichoderma lixii CR700, isolated from enormously heavy metal polluted electroplating wastewater. In the batch study, actively growing CR700 was able to remove 84.6% of Cu²⁺ at the concentration 10 mg/L of Cu²⁺ within 120 h after incubation and the accumulated and surface adsorbed amount of Cu was 0.51 and 0.47 mg/g of dry biomass respectively. T. lixii CR700 also showed efficient Cu²⁺ removal potential in the pH ranges from 5.0 to 8.0, in the presence of other co-occurring contaminant such as heavy metal, anions and metabolic inhibitor as well from real tannery wastewater. Alteration on cell surface of Cu²⁺ treated mycelia of T. lixii CR700 was analyzed using scanning electron microscope. Fourier transform infrared spectroscopic analysis was performed to identify the role of surface functional group in Cu²⁺ adsorption which revealed that COO^─ functional group lead Cu²⁺ adsorption onto the surface of T. lixii CR700. Thus, T. lixii CR700 uses simultaneous surface sorption and accumulation mechanism in Cu²⁺ removal and can be potentially applied for bioremediation of Cu²⁺ contaminated wastewater in ecofriendly, safe and sustainable way.