Efficient production of mannosylerythritol lipids by a marine yeast Moesziomyces aphidis XM01 and their application as self-assembly nanomicelles

Abstract

Mannosylerythritol lipids (MELs) are one of the most promising biosurfactants because of their excellent physicochemical properties, high environmental compatibility, and various biological functions. In this study, a mangrove yeast strain Moesziomyces aphidis XM01 was identified and used for efficient extracellular MEL production. The MEL titer reached 64.5 ± 0.7 g/L at flask level within 7 days with the optimized nitrogen and carbon source of 2.0 g/L NaNO3 and 70 g/L soybean oil. Furthermore, during a 10-L two-stage fed-batch fermentation, the final MEL titer reached 113.6 ± 3.1 g/L within 8 days, with prominent productivity and yield of 14.2 g·L−1·day−1 and 94.6 g/g(glucose and soybean oil). Structural analysis indicated that the produced MELs were mainly MEL-A and its fatty acid profile was composed of only medium-chain fatty acids (C8–C12), especially C10 acids (77.81%). Further applications of this compound were evaluated as one-step self-assembly nanomicelles. The obtained MEL nanomicelles showed good physicochemical stability and antibacterial activity. In addition, using clarithromycin as a model hydrophobic drug, the MEL nanomicelles exhibited high loading capacity and could be used for the controlled and sustained drug release in low-pH environments. Therefore, M. aphidis XM01 is an excellent candidate for efficient MEL production, and the prepared MEL nanomicelles have broad application prospects in the pharmaceutical and cosmetic fields.

Bioconversion of non-food corn biomass to polyol esters of fatty acid and single-cell oils

“…The PEFA nano-micelles were prepared and characterized as previously reported [ 47 ]. Briefly, 1 mg/mL of PEFA dissolved in deionized water was subjected to ultrasonic treatment for 15 min (work for 2 s, pause for 2 s), and was diluted to a series of concentrations from 0.5 to 100 mg/L.…”

Promising Application, Efficient Production, and Genetic Basis of Mannosylerythritol Lipids

“…Sodium nitrate (NaNO 3 ) is commonly employed as a nitrogen source for microbial growth in the production of MELs. For example, a recent study demonstrated that the physiological alkaline salts of NaNO 3 and potassium nitrate (KNO 3 ) led to significantly higher MEL titers of approximately 60 g/L, while the physiological acidic salts of ammonium nitrate (NH 4 NO 3 ) and ammonium sulfate ((NH 4 ) 2 SO 4 ) did not result in MEL production; despite this, NaNO 3 was determined to be the most effective nitrogen source when considering the cost factors, and the highest MEL yield was achieved when the concentration of NaNO 3 was 2.0 g/L [121] (Table 1). In 2020, Beck et al investigated the growth of seven Ustilaginaceae species with three different liquid culture media containing the same concentrations of glucose and sodium nitrate but different amount of mineral salts, vitamins, or trace elements, and it was shown that high concentrations of vitamins and trace elements are necessary for the cell growth of Ustilaginaceae fungi and successive MEL production from rapeseed oil [149].…”

“…In these cultures, olive oil is enzymatically digested into fatty acids and glycerol through the action of lipase secreted by M. antarcticus T-34 and subsequently absorbed by the cells. More recently, a mangrove yeast strain M. aphidis XM01 identified from mangrove plants was employed for efficient extracellular MEL production through a two-stage fed-batch bioprocess [121]. In this two-stage fed-batch fermentation, the final MEL titer per 10 L system reached 113.6 ± 3.1 g/L within 8 days, with prominent productivity and a yield of 14.2 g•L −1 •day −1 and 94.6 g/g (glucose and soybean oil) ; so, the M. aphidis XM01 strain is supposed to be an alternative microbial cell factory for industrial production of MELs from soybean oil [121].…”

“…More recently, a mangrove yeast strain M. aphidis XM01 identified from mangrove plants was employed for efficient extracellular MEL production through a two-stage fed-batch bioprocess [121]. In this two-stage fed-batch fermentation, the final MEL titer per 10 L system reached 113.6 ± 3.1 g/L within 8 days, with prominent productivity and a yield of 14.2 g•L −1 •day −1 and 94.6 g/g (glucose and soybean oil) ; so, the M. aphidis XM01 strain is supposed to be an alternative microbial cell factory for industrial production of MELs from soybean oil [121]. Structural composition analysis by using GC/MS showed that the MELs produced by the strain XM01 have good physicochemical stability, antibacterial activity, and encapsulation and release behavior, and are supposed to have broad application prospects in the pharmaceutical and cosmetic fields [121].…”

“…Temperature is a key factor affecting microbial growth and metabolism. By comparing the fermentation effects at different temperatures, it was found that 27-30 • C is the most suitable temperature (Table 1) [106,121,140,151]. The pH value has a significant impact on the growth of microorganisms and the synthesis of metabolites, and the optimal pH of different strains may vary significantly.…”