Microbe cultivation guidelines to optimize rhamnolipid applications

In the growing landscape of interest in natural surfactants, selecting the appropriate one for specific applications remains challenging. The extensive, yet often unsystematized, knowledge of microbial surfactants, predominantly represented by rhamnolipids (RLs), typically does not translate beyond the conditions presented in scientific publications. This limitation stems from the numerous variables and their interdependencies that characterize microbial surfactant production. We hypothesized that a computational recipe for biosynthesizing RLs with targeted applicational properties could be developed from existing literature and experimental data. We amassed literature data on RL biosynthesis and micellar solubilization and augmented it with our experimental results on the solubilization of triglycerides (TGs), a topic underrepresented in current literature. Utilizing this data, we constructed mathematical models that can predict RL characteristics and solubilization efficiency, represented as logPRL = f(carbon and nitrogen source, parameters of biosynthesis) and logMSR = f(solubilizate, rhamnolipid (e.g. logPRL), parameters of solubilization), respectively. The models, characterized by robust R2 values of respectively 0.581-0.997 and 0.804, enabled the ranking of descriptors based on their significance and impact-positive or negative-on the predicted values. These models have been translated into ready-to-use calculators, tools designed to streamline the selection process for identifying a biosurfactant optimally suited for intended applications.

Fermentative Production of Mannosylerythritol Lipids using Sweetwater as Waste Substrate by Pseudozyma antarctica (MTCC 2706)

Mannosylerythritol lipids are glycolipid biosurfactants with promising industrial applications. However, their commercial production is hindered due to its high production cost. The current study investigates the use of sweetwater, a by-product of the fat-splitting industry in combination with soybean oil for the production of mannosylerythritol lipids using Pseudozyma antarctica (MTCC 2706). The optimum sweetwater and soybean oil concentration of 22% and 7% (w/v) yielded 7.52 g L–1and 21.5 g L–1 mannosylerythritol lipids at shake flask and fermenter level respectively. The structure and functional groups of mannosylerythritol lipids were confirmed by fourier transform infrared (FTIR) spectroscopy, liquid chromatography-mass spectrometry (LC/MS) and 1H- and 13C-nuclear magnetic resonance (NMR) analysis. Surfactant properties, such as surface tension, critical micelle concentration, foaming and emulsification of mannosylerythritol lipids were also explored.