Biosurfactants are a microbially synthesized alternative to synthetic surfactants, one of the most important bulk chemicals. Some yeast species are proven to be exceptional biosurfactant producers, while others are emerging producers. A set of factors affects the type, amount, and properties of the biosurfactant produced, as well as the environmental impact and costs of biosurfactant’s production. Exploring waste cooking oil as a substrate for biosurfactants’ production serves as an effective cost-cutting strategy, yet it has some limitations. This review explores the existing knowledge on utilizing waste cooking oil as a feedstock to produce glycolipid biosurfactants by yeast. The review focuses specifically on the differences created by using raw cooking oil or waste cooking oil as the substrate on the ability of various yeast species to synthesize sophorolipids, rhamnolipids, mannosylerythritol lipids, and other glycolipids and the substrate’s impact on the composition, properties, and limitations in the application of biosurfactants.

Seaweed biomass is washed ashore on beaches causing recreational problems for local inhabitants and tourists. The management of marine waste in Latvia is not well developed. Brown algae Fucus vesiculosus is one of the most abundant seaweeds in Latvia. The chemical composition of brown algae Fucus vesiculosus, collected from the Gulf of Riga, was evaluated. Algae contain higher amounts of both macroelements (490 – 21500ppm; P, K, Ca, Mg, Na, Fe, Mn) and trace elements (0.11 – 930ppm; Zn, Cu, Cr, Pb, Sr, As, Cd, Se) than terrestrial plants. The obtained composition was used to describe the potential uses of seaweed. Food, pharmacy and bioenergy were considered as potentially the best sectors for macroalgae use. Due to high levels of heavy metals in seaweed, it is not recommended to use F. vesiculosus from Gulf of Riga as a food. The best potential use is found to be using it as biomass feed to obtain biogas

The biorefinery industry is witnessing a transition from fossil and chemical-based processes to more sustainable practices, with a growing emphasis on using renewable resources. Sophorolipids, a promising group of biosurfactants, present a viable substitute for conventionally produced surfactants. This study focuses on microbial fermentation using yeast and lipid substrate for sophorolipid production. The life cycle assessment (LCA) methodology was employed to identify environmental hotspots of the process and to assess the environmental benefits resulting from the replacement of raw rapeseed cooking oil (base scenario) with waste cooking oil, reduction of process electricity consumption, and increased sophorolipid yield. By compiling scenarios with the lowest environmental impact, a best-case scenario was created. The results revealed that the environmental impact of sophorolipid production could be reduced by 50% in the best-case scenario compared to the base scenario. This research provides valuable insights into the environmental optimization of the fermentation process and through the application of LCA highlights the potential for the reduction of negative environmental impact of sophorolipid production, contributing to the ongoing transition from petroleum oil and petrochemical refineries to sustainable biorefineries.