Bioconversion of iodoacetophenones by marine fungi

Marine-derived fungi as biocatalysts

Marine microorganisms account for over 90% of ocean biomass and their diversity is believed to be the result of their ability to adapt to extreme conditions of the marine environment. Biotransformations are used to produce a wide range of high-added value materials, and marine-derived fungi have proven to be a source of new enzymes, even for activities not previously discovered. This review focuses on biotransformations by fungi from marine environments, including bioremediation, from the standpoint of the chemical structure of the substrate, and covers up to September 2022.

Trichoderma species from plant and soil: An excellent resource for biosynthesis of terpenoids with versatile bioactivities

BACKGROUND

Trichoderma species are rich source of bioactive secondary metabolites. In the past decades, a series of secondary metabolites were reported from different Trichoderma fungi, among which terpenoids possessing versatile structural diversities and extensive pharmacological activities are one of the particularly important categories.

AIM OF REVIEW

The review aims to summarize the terpenoids isolated from Trichoderma species regarding their structural diversities, biological activities, and promising biosynthetic potentials.

KEY SCIENTIFIC CONCEPTS OF REVIEW

So far, a total of 253 terpenoids, including 202 sesquiterpenes, 48 diterpenes, 2 monoterpenes and 1 meroterpenoid, were isolated and identified from Trichoderma species between 1948 and 2022. Pharmacological investigations of Trichoderma terpenoids mainly focused on their antibacterial activities, antifungal activities, inhibitory activities on marine plankton species and cytotoxic activities, indicating that Trichoderma species are important microbial agents for drug discovery and environmentally friendly agrochemicals development. Intriguing chemistry and enzymology involved in the biosynthesis of Trichoderma terpenoids were also presented to facilitate further precise genome mining-guided novel structure discovery. Taken together, the abundance of novel skeletons, bioactivities and biosynthetic potentials presents new opportunities for drug and agrochemicals discovery, genome mining and enzymology exploration from Trichoderma species. The work will provide references for the profound study of terpenoids derived from Trichoderma, and facilitate further studies on Trichoderma species in the areas of chemistry, medicine, agriculture and microbiology.

Biotransformation of artemisinic acid to bioactive derivatives by endophytic Penicillium oxalicum B4 from Artemisia annua L

As a biosynthetic precursor of the antimalarial drug artemisinin, artemisinic acid (AA) is abundant in Artemisia annua L. with a content of 8-10-fold higher than artemisinin, but less effective. In this study, the biotransformation of AA was carried out with an endophytic fungus Penicillium oxalicum B4 to extend its utility. After 10-day-culture of the endophyte with AA at 2 mg/mL, eight biotransformation metabolites were isolated from the culture broth, including five undescribed metabolites, namely 3α,14-dihydroxyartemisinic acid, 14-hydroxy-3-oxo-artemisinic acid, 15-hydroxy-3-oxo-artemisinic acid, 12, 15-artemisindioic acid and 1,2,3,6-tetradehydro-12, 15-artemisindioic acid. The fungal enzymes possess the selective capacity to hydroxylate, carbonylate and ketonize the allyl group of AA. The major biotransformation metabolite was the hydroxylated product 3-α-hydroxyartemisinic acid (33.3%) in the cultures of early stage (day 1-6), whereas most of the other biotransformation products were synthesized in the later stage (day 8-10). Compared with AA, some metabolites (3α,14-dihydroxyartemisinic acid, 15-hydroxy-3-oxo-artemisinic acid and 1,2,3,6-tetradehydro-12, 15-artemisindioic acid) possessed stronger cytotoxic activity to the human colon carcinoma cell line (LS174T) and promyelocytic leukemia cell line (HL-60). The metabolites 12, 15-artemisindioic acid and 3-α-hydroxyartemisinic acid exhibited significant inhibitory activity to the lipopolysaccharide-induced nitrite production of RAW 264.7 cells at 10.00 μM and 2.50 μM, respectively. The results demonstrated the potential of fungal endophytes on biotransforming AA to its bioactive derivatives.

Synthesis of Knoevenagel Adducts Under Microwave Irradiation and Biocatalytic Ene-Reduction by the Marine-Derived Fungus Cladosporium sp. CBMAI 1237 for the Production of 2-Cyano-3-Phenylpropanamide Derivatives

The organic synthesis has been driven by the need of sustainable processes, which also requires efficiency and cost-effectiveness. In this work, we described the synthesis of nine Knoevenagel adducts between cyanoacetamide and aromatic aldehydes ((E)-2-cyano-3-(phenyl)acrylamide derivatives), employing triethylamine as catalyst under microwave irradiation in 30 min with excellent yields (93-99% yield). Then, these adducts were employed in the C-C double bond bioreduction by the marine-derived fungus Cladosporium sp. CBMAI 1237 for obtention of 2-cyano-3-phenylpropanamide derivatives in mild conditions and short reaction time for a whole-cells reduction (phosphate buffer pH 7.0, 32 °C, 130 rpm, 8 h) with good yields (48-90%). It is important to emphasize that the experimental conditions, especially the reaction time, should be carefully evaluated for the obtention of high yields. Since a biodegradation process consumed the obtained product in extended periods, probably due to the use of the substrate as carbon and nitrogen source. This approach showed that the use of coupled and greener catalysis methods such as microwave irradiation and biocatalytic reduction, which employs unique biocatalysts like marine-derived fungi, can be an interesting tool for the obtention of organic molecules.

Biodegradation of anthracene and several PAHs by the marine-derived fungus Cladosporium sp. CBMAI 1237

The biodegradation of polycyclic aromatic hydrocarbons (PAHs) by marine-derived fungi was reported in this work. Marine-derived fungi (Trichoderma harzianum CBMAI 1677, Cladosporium sp. CBMAI 1237, Aspergillus sydowii CBMAI 935, Penicillium citrinum CBMAI 1186 and Mucor racemosus CBMAI 847) biodegraded anthracene (14days, 130rpm, 50mgmL^-1 initial concentration in malt 2% medium). Cladosporium sp. CBMAI 1237 was the most efficient strain and biodegraded more anthracene in the presence (42% biodegradation) than in the absence (26%) of artificial seawater, suggesting that the biodegradation of PAHs may be faster in seawater than in non-saline environment. After 21days, Cladosporium sp. CBMAI 1237 biodegraded anthracene (71% biodegradation), anthrone (100%), anthraquinone (32%), acenaphthene (78%), fluorene (70%), phenanthrene (47%), fluoranthene (52%), pyrene (62%) and nitropyrene (64%). Previous undocumented metabolites were identified and, anthraquinone was a common product of different PAHs biodegradation. The marine-derived fungus Cladosporium sp. CBMAI 1237 showed potential for bioremediation of PAHs.

Recent Advances in Marine Enzymes for Biotechnological Processes

In the last decade, new trends in the food and pharmaceutical industries have increased concern for the quality and safety of products. The use of biocatalytic processes using marine enzymes has become an important and useful natural product for biotechnological applications. Bioprocesses using biocatalysts like marine enzymes (fungi, bacteria, plants, animals, algae, etc.) offer hyperthermostability, salt tolerance, barophilicity, cold adaptability, chemoselectivity, regioselectivity, and stereoselectivity. Currently, enzymatic methods are used to produce a large variety of products that humans consume, and the specific nature of the enzymes including processing under mild pH and temperature conditions result in fewer unwanted side-effects and by-products. This offers high selectivity in industrial processes. The marine habitat has been become increasingly studied because it represents a huge source potential biocatalysts. Enzymes include oxidoreductases, hydrolases, transferases, isomerases, ligases, and lyases that can be used in food and pharmaceutical applications. Finally, recent advances in biotechnological processes using enzymes of marine organisms (bacterial, fungi, algal, and sponges) are described and also our work on marine organisms from South America, especially marine-derived fungi and bacteria involved in biotransformations and biodegradation of organic compounds.

Induction, expression and characterisation of laccase genes from the marine-derived fungal strains Nigrospora sp. CBMAI 1328 and Arthopyrenia sp. CBMAI 1330

The capability of the fungi Nigrospora sp. CBMAI 1328 and Arthopyrenia sp. CBMAI 1330 isolated from marine sponge to synthesise laccases (Lcc) in the presence of the inducer copper (1–10 μM) was assessed. In a liquid culture medium supplemented with 5 μM of copper sulphate after 5 days of incubation, Nigrospora sp. presented the highest Lcc activity (25.2 U·L⁻¹). The effect of copper on Lcc gene expression was evaluated by reverse transcriptase polymerase chain reaction. Nigrospora sp. showed the highest gene expression of Lcc under the same conditions of Lcc synthesis. The highest Lcc expression by the Arthopyrenia sp. was detected at 96 h of incubation in absence of copper. Molecular approaches allowed the detection of Lcc isozymes and suggest the presence of at least two undescribed putative genes. Additionally, Lcc sequences from the both fungal strains clustered with other Lcc sequences from other fungi that inhabit marine environments.

Biotransformation of methylphenylacetonitriles by Brazilian marine fungal strain Aspergillus sydowii CBMAI 934: eco-friendly reactions

This study reports the biotransformation of methylphenylacetonitriles by Brazilian marine filamentous fungus Aspergillus sydowii CBMAI 934 under eco-friendly reaction conditions. The phenylacetonitrile 1, 2-methylphenylacetonitrile 2, 3-methylphenylacetonitrile 3, and 4-methylphenylacetonitrile 4 were quantitatively biotransformed into 2-hydroxyphenylacetic 1a, 2-methylphenylacetic acid 2a, 3-methylphenylacetic acid 3a, and 4-methylphenylacetic acid 4a by enzymatic processes using whole cell as biocatalyst. The marine fungus A. sydowii CBMAI 934 is thus a promising biocatalyst for the preparation of important carboxylic acids under mild conditions (pH 7.5 and 32 °C) from nitrile compounds.