Biosurfactant
Surfactants, also known as surfactants, are compounds that can significantly reduce the surface tension or interfacial tension between two liquids, between liquids and gases, and between liquids and solids. The molecular structure of surfactants is amphoteric: hydrophilic groups at one end and hydrophobic groups at the other; hydrophilic groups are often polar groups, such as carboxylic acid, sulfonic acid, sulfuric acid, etc., and hydrophobic groups are often nonpolar hydrocarbon chains, such as hydrocarbon chains with more than 8 carbon atoms.
Surfactants are able to remove stains from the surface of objects by reducing the surface tension of water, emulsifying and dispersing stains, and providing emulsion stability. And they form a film between the liquid and the gas. This film prevents gases from escaping from the liquid, resulting in a stabilized foam.
Principle of Surfactant Stain Removal / Foam Stabilization
As people pay more attention to their health and environmental protection, detergents and surfactants are increasingly being developed in the direction of being gentle, green and natural. Among different types of surfactants, biosurfactants are gradually replacing traditional surfactants due to their effective surface activity, excellent compounding properties, biodegradability, non-irritation, and personal safety.
Biosurfactant
RURAL VITALIZATION
Biosurfactants have excellent surface activity, diverse varieties and strong selectivity. They are non-toxic and easy to degrade, showing good environmental compatibility, the important thing is that microorganisms can directly use organic waste to synthesize biosurfactants with special life activity, effectively dispersing and completely degrading organic matter, that is, to realize the management of organic pollution.
Chemical synthesis of surfactants lead to eutrophication of water bodies
At present, most surfactants on the market are chemically synthesized, but the use of chemical surfactants will produce serious environmental pollution problems. In recent years, with the enhancement of people’s awareness of environmental protection and the concept of sustainable development, biosurfactants produced by microorganisms have received widespread attention. Compared with chemical surfactants, biosurfactants have many advantages: low/non-toxicity, high biocompatibility and biodegradability.
Based on the molecular weight, biosurfactants are classified into two categories: low molecular weight surfactants, which effectively reduce surface and interfacial tensions, and high molecular weight emulsifiers, which help to improve the stability of emulsions. There is a wide variety of biosurfactants of microbial origin, which can be broadly classified into five categories according to their chemical composition and producing strains: glycolipids, phospholipids, lipopeptides and lipoproteins, hydroxylated or cyclic fatty acids, and polymeric or special surfactants.
Glycolipid biosurfactants
Glycolipid biosurfactants are the most common and readily available biosurfactants, which are complexes of carbohydrates and long-chain fatty acids linked by ether or ester groups. Common glycolipid surfactants include rhamnolipids produced by Pseudomonas aeruginosa, alginate lipids produced by Rhodococcus erythropolis and Bacillus staphylococcus as well as acacia glycolipids produced by Pseudomonas solanacearum and Saccharomyces cerevisiae.
Glycolipid surfactant rhamnolipid
Rhamnolipid is the most studied glycolipid surfactant. The hydrophilic group is one or two molecules of rhamnose, and the hydrophobic group is one or two β-hydroxylated saturated or unsaturated fatty acid chains. These groups are interconnected to form a variety of homologs with similar chemical structures. The outstanding property of glycolipids is their ability to significantly reduce surface tension. In addition, rhamnolipids are also able to modify the wettability of solid surfaces and have a variety of functions such as emulsification, defoaming, washing, dispersing, antistatic and lubrication.
