Bacterial-derived surfactants: an update on general aspects and forthcoming applications

Abstract

The search for sustainable alternatives to the production of chemicals using renewable substrates and natural processes has been widely encouraged. Microbial surfactants or biosurfactants are surface-active compounds synthesized by fungi, yeasts, and bacteria. Due to their great metabolic versatility, bacteria are the most traditional and well-known microbial surfactant producers, being Bacillus and Pseudomonas species their typical representatives. To be successfully applied in industry, surfactants need to maintain stability under the harsh environmental conditions present in manufacturing processes; thus, the prospection of biosurfactants derived from extremophiles is a promising strategy to the discovery of novel and useful molecules. Bacterial surfactants show interesting properties suitable for a range of applications in the oil industry, food, agriculture, pharmaceuticals, cosmetics, bioremediation, and more recently, nanotechnology. In addition, they can be synthesized using renewable resources as substrates, contributing to the circular economy and sustainability. The article presents a general and updated review of bacterial-derived biosurfactants, focusing on the potential of some groups that are still underexploited, as well as, recent trends and contributions of these versatile biomolecules to circular bioeconomy and nanotechnology. Graphical Abstract

Green Surfactants (Biosurfactants): A Petroleum-Free Substitute for Sustainability─Comparison, Applications, Market, and Future Prospects

“…However, a comprehensive summary by Hommel and Ratledge 155 may be handy to read. Per Syldatk and Wagner, 157 there are four possibilities which can exist for synthesis of linkages and involved hydrophilic (HPL) and hydrophobic (HB) moieties of biosurfactants: 158 (1) HPL and HB moieties synthesized de novo by two independent pathways (2) HPL synthesized de novo and HB induced by substrate (3) HB synthesized de novo and HPL substrate dependent (4) overall generalization that can be made as each mechanism and route will be different as suggested above.…”

“…The term “surfactant” comes from “surface active agents”, which are molecules that adsorb on the water–surface interface and reduce water’s surface tension to enhance the cleaning of surfaces. , They are also known as amphiphiles because they have polar heads, also known as hydrophilic heads, that have an attraction for polar solvents, and nonpolar tails, also known as hydrophobic tails. , The molecular structures of these molecules help reduce the cohesive forces between water molecules, resulting in the lowering of surface tension. − They possess other qualities that allow them to be used in applications other than lowering surface tension , such as emulsifiers, − foaming agents, − corrosion inhibitors, − and antistatic agents. − Surfactants have been used in practically every industry because of their physicochemical characteristics . These include paints, inks, , coatings, − adhesives, paper and pulp, petroleum and oil, plastics, resins, textiles and fibers, detergents, agricultural, food, cosmetics, pharmaceutical, and various industrial applications .…”

Ecofriendly Natural Surfactants in the Oil and Gas Industry: A Comprehensive Review

“…In addition to the above-mentioned surfactants, the literature has reported several other natural surfactants. Some other important classes of natural surfactants are fatty acids, neutral lipids, emulsan, and liposan, among others. ,− …”