Application of biosurfactants in herbicide mobilization and nanoparticle synthesis
Loading...
Date
2021-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU, Hisar
Abstract
Present study traversed cheaper renewable raw material, butter waste for biosurfactant production by four yeasts, Meyerozyma guilliermondii YK20, M. guilliermondii YK21, M. guilliermondii YK22 and M. guilliermondii Y32 followed by its extraction in crude form designated as BS20, BS21, BS22 and BS32, respectively, using acid precipitation. The crude products were allocated to respective classes and subclasses of biosurfactants using advanced characterization techniques before exploring their application in herbicide mobilization and nanoparticle synthesis. Acid precipitation method was able to yield 11.19 (pH 3.5), 12.55 (pH 3.0), 15.13 (pH 3.5) and 18.64g/L (pH 4.0) of biosurfactant BS20, BS21, BS22 and BS32, respectively. The crude biosurfactants BS20, BS21, BS22 and BS32 were found retaining and concentrating the surfactant activity ascertained in the form of oil displacements amounted to 48.0, 48.0, 50.0 and 55.2cm, respectively, as oppose to corresponding values of 5.5, 6.0, 7.5 and 8.0cm generated by cell free supernatants prior to extraction. Agar double diffusion technique confirmed the anionic nature of all the four products. Zeta potential of 33.2, 39.6, 69.8 and 200 mV with negative polarity signified moderate to excellent stability in case of BS32, BS21, BS20 and BS22, respectively. The biochemical analysis revealed the presence of lipid, proteins and carbohydrate fractions in all the four biosurfactants, underlining lipid as the major constituent ranging from 42-54%. FTIR spectra of biosurfactants have shown the glycolipid nature of all the biosurfactants due to the presence of carbonyl group, O-H, C-H and C-O stretching vibrations. The NMR spectra further indicated the presence of sophorose moiety confirming sophorolipid subclass of all the biosurfactants. The SEM micrographs revealed the polymeric nature and long-range order of all the biosurfactants while EDX spectra indicated the dominance of carbon and oxygen showing the prevalence of carbohydrate and lipid moieties. None of the biosurfactants exhibited any toxicity against chickpea (HC-1) and wheat (WH-1105) or any antimicrobial activity towards common soil inhabitants. The application of biosurfactant BS32 as adjuvant to herbicide glyphosate produced similar mortality at lower doses (75% and 50% of recommended dose) as produced by the chemical surfactant at recommended doses in Chenopodium album and Rumex dentatus, thereby, conversing a role in dose reduction of herbicide under test. Biosurfactant BS32 has also been detected as a potential replacement to chemical surfactant in metsulfuron methyl formulation at the recommended dose. Biosurfactant BS32, at 0.5% concentration played as reducing as well as stabilizing agent in synthesizing ZnO nanoparticles with spherical morphology and average size of 7.04nm as evaluated using HR-TEM analysis.