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.

Intramolecular hydrogen bonds influence intermolecular binding in adsorption and molecular recognition, but the interplay between intra- and intermolecular hydrogen bonding is poorly understood. In this study, a series of four aromatic alcohols, 2-phenylethanol, 3-phenyl-1-propanol, 2-phenoxyethanol, and 3-phenoxy-1-propanol, are examined to determine the effect of intramolecular hydrogen bond formation on the binding to ethyl propionate (EP), an analogue of an acrylic ester separation resin. A combination of infrared spectroscopy, molecular modeling, and ab initio calculations are used to investigate the conformational preferences of the alcohols and the alcohol:EP complexes in hexane. Without EP, 2-phenylethanol and 2-phenoxyethanol prefer intramolecularly hydrogen-bonded conformations, whereas 3-phenyl-1-propanol overwhelmingly favors a conformer without an intramolecular hydrogen bond. For 3-phenoxy-1-propanol, there is a smaller preference for conformers without an intramolecular hydrogen bond. These results agree qualitatively with the experimentally measured IR spectra. The conformational preferences are explained by examining the energy components of low-energy conformers. Electrostatic interactions favor the intramolecularly hydrogen-bonded species, whereas the dihedral energy term and entropic term favor conformers without an intramolecular hydrogen bond. The balance determines the most stable conformer. The calculations predict that all four alcohols bind EP weakly compared with para-methoxyphenol. This ranking is in good agreement with experimental adsorption measurements. The small calculated ΔG° values of ≈ −0.9 to −2.4 kJ/mol for the alcohols is explained in terms of hydrogen bond donating ability, entropy, and the competition between inter- and intramolecular hydrogen bonds.

Various oxygenated aromatic compounds (OACs) could be obtained from renewable resources if separations were available to fractionate the complex mixtures. We examined adsorption for the fractionation of OACs into (i) acids, (ii) phenols, (iii) alcohols, and (iv) compounds lacking hydrogen-bond donating ability. Specifically, we studied adsorption from a nonpolar solvent onto a neutral acrylic ester sorbent. The acid, 3-phenylpropionic acid, exists in hexane as monomers and self-associated (e.g., dimeric) species. Phenomenological evidence indicates that monomers can adsorb but that adsorption competes with solution-phase dimerization. Previous studies indicate that phenols and alcohols adsorb through a hydrogen-bonding mechanism, while OACs lacking hydrogen-bond donating ability (i.e. aldehydes, ketones, esters, and ethers) adsorb weakly. Isotherms show that these four classes of OACs adsorb with significantly different affinities. Desorption is achieved by exploiting deprotonation reactions in an aqueous desorption phase and that the acids and phenols can be selectively desorbed based on differences in their pK a 's. A potential approach for fractionating renewable OACs is considered.