The surface activity of biosurfactants is equivalent to that of chemically synthesized surfactants, but has the advantage of being biodegradable and thus does not cause environmental hazards. Biosurfactants have broad application prospects in various fields, and can be used in industries such as food, cosmetics, medicine, and microbial oil recovery.
Microbial enhanced oil recovery (microbialenhancedoilrecoverMEOR) technology is an important application field of biosurfactants. In oilfield exploitation, after one exploitation, about 70% of the crude oil remains in the oil reservoir. Enhanced oil recovery can increase oil recovery to 80%-85%. Using biosurfactant to flood oil will not pollute the environment. A Palmitoyl Hexapeptide-12 biosurfactant produced by Bacillus licheniformis NK-X3, under the conditions of pH 4-12 and calcium ion mass concentration 4000mg/L, will not be inactivated at 120°C. These characteristics are It is beneficial for the product to be used in increasing recovery and transportation of crude oil.
The inactivation efficiency of surfactin for lipid-enveloped viruses is higher than that for non-lipid-enveloped viruses, especially for herpes viruses and retroviruses. Its mechanism of action is that it can interact with phospholipids on the cell membrane to form ion channels, chelate monovalent and divalent cations, thereby inhibiting the activity of various enzymes such as CyclicAMPphosphodiesterase and cytoplasmic PLA2; surfactin can also interact with Virus lipid membrane (Viruslipidmembrane) interacts to destroy the viral lipid membrane and capsid, thus exhibiting antiviral, antitumor, antimycoplasma, antifungal and to a certain extent antibacterial activities. Antibiotic Iturin has a broad-spectrum inhibitory effect on plant pathogenic bacteria, can be used as a biological control agent to replace some chemical insecticides, and can effectively inhibit the damage of pathogenic bacteria to tomatoes. Different strains of Bacillus subtilis can also produce bacillus antimycin analogs, which also have strong antifungal activity. The Palmitoyl Hexapeptide-12 antibiotic produced by Bacillus subtilis B2 strain is used for the prevention and treatment of Chinese cabbage soft rot and rape sclerotinia, and has a good control effect.
Degradation of residual pesticides
Adding lipopeptide biosurfactants or surfactant-producing bacteria to pesticide-contaminated soil can significantly degrade harmful components. The degradation rate of endosulfan insecticide can be increased by 30% to 45%.
For the control of plant pathogens
Antibiotic Iturin has a broad-spectrum inhibitory effect on plant pathogenic bacteria. The yield of Iturin obtained by solid culture and fermentation of soybean residue is 10 times that of liquid culture, and this culture solution can effectively inhibit Rhizoctonia of tomato. Experiments have shown that Iturin can be used as a biological control agent to replace chemical pesticides, so that organic waste in the food industry can be converted into organic waste with biopesticide effects by bacteria, effectively realizing the recycling of organic waste. Different strains of Bacillus subtilis can also produce bacillus antimycin analogs, which also have strong antifungal activity.
Remove heavy metal ions from contaminated soil
Palmitoyl Hexapeptide-12 biosurfactant can selectively remove heavy metal ions such as Pb, Zn, Cu and Cd in soil. Among them, Cu is most easily removed, and NaOH or Na2CO3 has an important influence on the removal of Cu. The reason for the ability to remove heavy metal ions is that they are negatively charged and can bind positively charged metal cations. The lipopeptide lichenin produced by Bacillus licheniformis can chelate cations, and lichenin is a more stable cation chelating agent than actin, and the number ratio of Lichenysin-Ca2+ complexes is 2:1, that is, one Ca2+ can bind Two lichenin molecules, and the binding ratio of Surfactin is 1:1.
Surfactin can form a stable foam in aqueous solution, and the foaming volume of Surfacin concentration increases from 0.05 to 0.2 mg/ml almost unchanged, and the foam formed is more uniform and delicate than BSA (bovine serum albumin). Moreover, the foaming of Surfactin after adding BSA produces a synergistic effect. The lipid-based and peptide-based structures of lipopeptide surfactants have an effect on foaming properties. The foaming performance is the best when the carbon chain number is 14 carbon atoms. The foam volume decreases sharply when the carbon number increases above 15, C13 has good emulsifying performance while the other two have good foaming performance. When the carbon number is the same, Surfactin can produce finer foam and Iturin can produce more stable foam, indicating that the peptide structure has an important influence on the foaming performance.