Glycolipopeptide biosurfactant produced by Klebsiella pneumoniae ssp. ozaenae BK34: Virtue in germination and growth of chickpea (Cicer arietinum L.) HC-1 crop

Abstract

Modern agriculture consumes many persistent and non-biodegradable agrochemicals enhancing production and economy for farmers. Besides, chemical surfactants are used as adjuvant to augment the action of agrochemicals. A toxicity concern of these agrochemicals and adjuvants on life forms and environment cannot be ignored. Microbiologically produced, eco-friendly, biodegradable surfactants could be suggested as an alternative, however, compatibility with plants and beneficial microflora needs to be ascertained before applying them into agriculture. The current study included evaluation of biosurfactant BS34 produced by Klebsiella pneumoniae BK34 towards germination and growth of chickpea [Cicer arietinum (L.)] seeds. The biosurfactant BS34 was characterized as surfactin like glycolipopeptide based on Fourier transform infrared spectroscopy and Liquid chromatography-Mass spectrometry characterization. The biosurfactant was found non-phytotoxic during in-vitro germination of chickpea seeds as evident from very high germination index of 187.74 as opposed to the almost negligible germination index of 0.04 shown by highly phytotoxic chemical surfactant. In comparison to control, the biosurfactant seed treatment [1%(w/v)] in an in-vivo study on chickpea increased the plant height by 18%, nodule number by 11.13%, nodule fresh weight by 12.66% shoot weight by 11.20% and root weight by 34.61%. Contrarily, seed treatment by 1% (w/v) sodium dodecyl sulfate (SDS) inhibited the germination and growth of chickpea seeds again documenting superiority of biosurfactants over their chemical counterparts. Improved seed germination, growth and yield attributes of chickpea crop in presence of non-phytotoxic glycolipopeptide biosurfactant produced by Klebsiella pneumoniae ssp. ozaenae BK34 suggests its potential as an alternative to chemical surfactants used in agriculture.