Surfactants find wide commercial use as foaming agents, emulsifiers, and dispersants. Currently, surfactants are produced from petroleum, or from seed oils such as palm or coconut oil. Due to concerns with CO(2) emissions and the need to protect rainforests, there is a growing necessity to manufacture these chemicals using sustainable resources In this report, we describe the engineering of a native nonribosomal peptide synthetase pathway (i.e., surfactin synthetase), to generate a Bacillus strain that synthesizes a highly water-soluble acyl amino acid surfactant, rather than the water insoluble lipopeptide surfactin. This novel product has a lower CMC and higher water solubility than myristoyl glutamate, a commercial surfactant. This surfactant is produced by fermentation of cellulosic carbohydrate as feedstock. This method of surfactant production provides an approach to sustainable manufacturing of new surfactants.

No abstract

Fatty-acyl-glutamate (FA-Glu), a surfactin variant has been successfully produced using a genetically modified strain of Bacillus subtilis grown on glucose. However, yields with soybean hulls (SBH) replacing glucose were lower. This work was undertaken to reduce the yield loss when using SBH as the carbon source and to evaluate two other soy by-products, namely fiber and skim from aqueous oil extraction as alternative carbon and nitrogen sources. Fermentation of soybean hulls, fibers and skim at various concentrations produced lower FA-Glu titers compared to S-7 medium. Neither increasing their amount nor supplementing with glucose increased the FA-Glu titer, suggesting the presence of an inhibitor in these feedstocks. By using a mixture of polysaccharidedegrading enzymes, over 65% of SBH solids were converted to soluble carbohydrates. FA-Glu titers obtained from SBH hydrolysates containing residual hull solids were still low; however, with the removal of the solids, cell growth improved and FA-Glu yield was 60% higher than with glucose. Thus, this low-cost material can be converted to a substrate for production of FA-Glu biosurfactant. Unmodified fiber and skim components of aqueous oil extraction were not beneficial.

No abstract