Direct biodegradation of eugenol to coniferyl aldehyde and other higher value-added products by Gibberella fujikuroi ZH-34

BACKGROUND: Eugenol is an economically favorable substrate for the microbial biotransformation of aromatic compounds. Coniferyl aldehyde is one kind of aromatic compound that is widely used in condiment and medical industries; it is also an important raw material for producing other valuable products such as vanillin and protocatechuic acid. However, in most eugenol biotransformation processes, only a trace amount of coniferyl aldehyde is detected, thus making these processes economically unattractive. As a result, an investigation of new strains with the capability of producing more coniferyl aldehyde from eugenol is required. RESULTS: We screened a novel strain of Gibberella fujikuroi, labeled as ZH-34, which was capable of transforming eugenol to coniferyl aldehyde. The metabolic pathway was analyzed by high-performance liquid chromatography­mass spectrometry and transformation kinetics. The culture medium and biotransformation conditions were optimized. At a 6 h time interval of eugenol fed-batch strategy, 3.76 ± 0.22 g/L coniferyl aldehyde was obtained, with the corresponding yield of 57.3%. CONCLUSIONS: This work improves the yield of coniferyl aldehyde with a biotechnological approach. Moreover, the fed-batch strategy offers possibility for controlling the target product and accumulating different metabolites

New stereoisomeric derivatives of jasmonic acid generated by biotransformation with the fungus Gibberella fujikuroi affect the viability of human cancer cells

Background: Several studies have shown that (-)-Jasmonic acid, (+)-7-iso-Jasmonic acid and its methyl ester, methyl jasmonate, have anti-cancer activity in vitro and in vivo, exhibiting selective cytotoxicity towards cancer cells. The degree of activity of these molecules is strongly related to their stereochemistry. The biotransformation of known compounds, natural or synthesized, related to interesting biological activities, generates new molecules displaying new improved properties compared with the original ones, increasing its value and providing new more effective products. Therefore, based on the above rationales and observations, in this work a biotransformation protocol to modify the chemical structure of the plant hormone jasmonic acid by using the fungus Gibberella fujikuroi was established. Results: The three jasmonic acid derivatives obtained, 3(S)-Hydroxy-2(R)-(2Z-pentenyl)-cyclopentane-1(R)-acetic acid (1), 3(R)-Hydroxy-2(R)-(2Z-pentenyl)-cyclopentane-1(R)-acetic acid (2), 3-Hydroxy-2(S)-(2Z-pentenyl)-cyclopentane-1(S)-acetic acid (3), were tested for cell-growth inhibition activity towards the human cancer epithelial cell line, the oral squamous carcinoma cells (KB). The results obtained show that jasmonic acid derivatives (1-3) are active on human cancer cells examined in different concentration ranges, with IC50 value less than of 25 uM. The compound 3, with the same molecular structure of compounds 1 and 2, but with different stereochemistry, was more active confirming that the activity of jasmonate compounds is related to their stereochemistry and to substituents in the cyclopentane ring. In this study, we also tested the potential proapoptotic activity of compound 3, and our data suggest that it, as other jasmonate compounds, is able to trigger apoptotic death in cancer cells. This event may be correlated at an elevation of reactive oxygen species (ROS). Administration of N-acetylcysteine (NAC) prevented compound 3 cytotoxicity...