Biosurfactants are metabolites secreted by microorganisms during their metabolic processes under specific cultivation conditions. Compared with chemically synthesized surfactants, biosurfactants possess many unique attributes, such as structural diversity, biodegradability, broad biological activity, and environmental friendliness. Due to factors like raw material availability, cost, and performance limitations of synthetic surfactants—coupled with their tendency to cause severe environmental pollution and pose risks to human health during production and use—research on biosurfactants has grown significantly over the past two decades as environmental and health awareness has increased. The field has developed rapidly, with numerous patents filed internationally for various biosurfactants and their production processes. In China, research has primarily focused on the application of biosurfactants in enhanced oil recovery and bioremediation.
1.Types of Biosurfactants and Producing Strains
1.1 Types of Biosurfactants
Chemically synthesized surfactants are typically classified based on their polar groups, whereas biosurfactants are categorized according to their biochemical properties and the producing microorganisms. They are generally divided into five types: glycolipids, phospholipids and fatty acids, lipopeptides and lipoproteins, polymeric surfactants, and specialized surfactants.
1.2 Producing Strains of Biosurfactants
Most biosurfactants are metabolites of bacteria, yeasts, and fungi. These producing strains are predominantly screened from oil-contaminated lakes, soil, or marine environments.
2.Production of Biosurfactants
Currently, biosurfactants can be produced via two main methods: microbial fermentation and enzymatic synthesis.
In fermentation, the type and yield of biosurfactants depend primarily on the strain of microorganism, its growth stage, the nature of the carbon substrate, the concentrations of N, P, and metal ions (such as Mg²⁺ and Fe²⁺) in the culture medium, as well as cultivation conditions (pH, temperature, agitation speed, etc.). The advantages of fermentation include low production costs, diversity of products, and simple processes, making it suitable for large-scale industrial production. However, the costs of separation and purification can be high.
In contrast, enzymatically synthesized surfactants often have relatively simpler molecular structures but exhibit equally excellent surface activity. Benefits of the enzymatic approach include lower extraction costs, ease of structural modification, straightforward purification, and the reusability of immobilized enzymes. Additionally, enzymatically synthesized surfactants can be used to produce high-value-added products, such as pharmaceutical components. Although enzyme costs are currently high, advances in genetic engineering to enhance enzyme stability and activity are expected to reduce production expenses.
Post time: Sep-04-2025