Biosurfactant production by halophilic yeasts isolated from extreme environments in Botswana

Abstract

Nine morphologically distinct halophilic yeasts were isolated from Makgadikgadi and Sua pans, as pristine and extreme environments in Botswana. Screening for biosurfactant production showed that Rhodotorula mucilaginosa SP6 and Debaryomyces hansenii MK9 exhibited the highest biosurfactant activity using Xanthocercis zambesiaca seed powder as a novel and alternative inexpensive carbon substrate. Chemical characterization of the purified biosurfactants by Fourier Transform Infra-Red spectroscopy suggested that the biosurfactant from R. mucilaginosa SP6 was a rhamnolipid-type whereas the biosurfactant from D. hansenii MK9 was a sophorolipid-type. The two biosurfactants exhibited antimicrobial activities against eight pathogenic bacteria and fungal strains (Proteus vulgaris, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Micrococcus luteus, Cryptococcus neoformans, Candida albicans and Aspergilus niger). The sophorolopid-type biosurfactant was found to be the most potent among the antimicrobial drug resistant strains tested. The findings open up prospects for the development of environmentally friendly antimicrobial drugs that use an inexpensive source of carbon to reduce the costs associated with the production of biosurfactants.

Diversity of dung beetle‐associated yeasts from pristine environments of Botswana

“…We also isolated R. mucilaginosa (3%) (Figure 3) at a lower frequency from Khumaga (Supporting Information: Figure S2a) and from two of the six species of dung beetles (Figure 3 and Supporting Information: Table S1). Previously isolated strains of this species have been found in various environments, including hydrocarboncontaminated soils (Chandran & Das, 2012), glacial ice (Butinar et al, 2007), hypersaline soils (Loeto et al, 2021), coastal waters (Fotedar et al, 2018;Gadanho et al, 2003), and freshwater lakes (Libkind et al, 2003). There are no records of this yeast being isolated from dung beetles, but its ability to use oils and fatty acids, as well as its capacity to produce antimicrobial compounds (Loeto et al, 2021), may be crucial characteristics needed for its association with dung beetles, whose diet may contain fats and provide protection from fungi pathogens, respectively.…”

Microbial Biosurfactant as an Alternate to Chemical Surfactants for Application in Cosmetics Industries in Personal and Skin Care Products: A Critical Review

“…Staphylococcus aureus , Pseudomonas aeruginosa , Candida acnes , and Streptococcus pyogenes are some skin pathogens inhibited by several different biosurfactants, which have been shown to have efficient inhibitory mechanisms. Due to this, biosurfactants have been proposed as a potential alternative to traditional antibiotics, even though the bactericidal action of biosurfactants is often weak and varies greatly from one molecule to another [ 102 ].…”

“…In contrast, cell-associated antimicrobial biosurfactants are more complex and can be identified by their multiple constituents, such as glycolipoproteins. However, information on conformations, molecular weight, and modes of action is still lacking [ 102 ].…”

Prospects of Microbial Bio‐surfactants To Endorse Prolonged Conservation in the Pharmaceutical and Agriculture Industries

“…[34] However, in modern times, researchers screen microbial isolates from various sources such as the ocean, polluted soil, medical waste, sewage, and heavy metal polluted sites. [35][36][37] The process of manufacturing biosurfactants involves culturing microbial strains, followed by their identification and characterization. To ensure successful growth and biosurfactant production, microbial cultures need to be cultivated under conditions that mimic their natural habitat and physical environment.…”