The microbial world provides new energy sources and many various ‘green’ chemicals. One type of chemicals produced by microorganisms is the biosurfactant group. Biosurfactants are universal molecules, exhibiting surface properties often accompanied by desired biological activity. Biosurfactants are considered to be environmentally ‘friendly’ due to their low toxicity and biodegradable nature. These compounds have unique features and therefore they can find potential applications in many different industries, ranging from biotechnology to environmental remediation technologies. Antibacterial and antifungal activities make them relevant for applications as inhibitory agents against microbial biofilm. This review covers the current knowledge and the recent advances in the field of biosurfactants as antibiofilm agents.

Atrazine, is one of major concern pesticides contaminating agricultural areas and ground water. Its microbial biodegradation seems to be the most efficient in terms of economic and environmental benefits. In the present work the cometabolic biodegradation of atrazine by the fungus Metarhizum robertsii IM 6519 during 10-day batch cultures was characterized. The herbicide was transformed to several hydroxy-, dechlorinated or dealkylated metabolites with the involvement of cytochrome P450 monooxygenases. The obtained metabolomics data revealed that atrazine induced oxidative stress (increased the levels of L-proline, L-ornithine, L-arginine, GABA and L-methionine), disruptions of the carbon and nitrogen metabolism (L-aspartic acid, L-asparagine, L-tyrosine, L-threonine, L-isoleucine, L-phenylalanine, 1-methyl-L-histidine, L-tryptophan, L-valine, L-alanine, O-phospho-L-serine, L-sarcosine or L-lysine) and caused an increase in the membrane fluidity (a rise in the phosphatidylcholines/phosphatidylethanolamines (PC/PE) ratio together with the growth of the taurine level). The increased level of hydroxyl derivatives of linoleic acid (9-HODE and 13-HODE) confirmed that atrazine induced lipid peroxidation. The presented results suggesting that M. robertsii IM 6519 might be applied in atrazine biodegradation and may bring up the understanding of the process of triazine biodegradation by Metarhizum strains.

Candida albicans is an opportunistic fungal pathogen of humans. Treatment of C. albicans infections relies on azoles, which target the lanosterol 14α-demethylase (Erg11p) encoded by the ERG11 gene. Our results show that targeted gene disruption of ERG11 can result in resistance to ergosterol-dependent drugs (azoles and amphotericin B), auxotrophy and aerobically viable erg11Δ/Δ cells. Abnormal sterol deposition and lack of ergosterol in the erg11Δ/Δ strain leads to reduced plasma membrane (PM) fluidity, as well as dysfunction of the vacuolar and mitochondrial membranes, resulting respectively in defects in vacuole fusion and a reduced intracellular ATP level. The altered PM structure of the erg11Δ/Δ strain contributes to delocalisation of H⁺-ATPase and the Cdr1 efflux pump from the PM to vacuoles and, resulting in a decrease in PM potential (Δψ) and increased sensitivity to ergosterol-independent xenobiotics. This new insight into intracellular processes under Erg11p inhibition may lead to a better understanding of the indirect effects of azoles on C. albicans cells and the development of new treatment strategies for resistant infections.