Abstract

The development of natural-based products is a contemporary trend, with biological cleaning agents playing a pivotal role in this movement. Increasing environmental concerns and the demand for safer, biodegradable alternatives to synthetic chemicals have further accelerated interest in such eco-friendly solutions. Garbage enzymes, which are biologically derived through the fermentation of organic waste, have emerged as promising candidates due to their sustainability and multifunctional applications, particularly in cleaning and household sanitation. In addition to its ability to degrade organic residues, garbage enzyme are also highly likely to harbor Bacillus species, which are well known for their ability to produce biosurfactants with strong surface-active properties. This study aims to isolate and screen Bacillus strains with biosurfactant-producing capabilities. A total of 20 strains were isolated from garbage enzyme. Among these, three strains exhibiting the highest biosurfactant production were selected based on cleaning capacity with oil spreading assay, a rapid and reliable method for assessing surface activity. 16S rRNA sequencing identified these three strains (B5, B6, and B8) as belonging to the genus Bacillus. Notably, after three days of cultivation, strains B5 and B6 expressed the gene encoding fengycin (lipopeptide biosurfactant with strong surface activity), while strain B8 exhibited both fengycin and iturin production. Fermentation assays utilizing soapberry with the three isolated strains demonstrated enhanced oil spreading and improved EC24 emulsification compared to fermentation with each individual strain and the soapberry extract without any added strains. However, the use of multiple strains in co-fermentation did not demonstrate higher biosurfactant production or EC24 values compared to single-strain fermentation. These findings underscore the potential of the three isolated Bacillus strains for the development of efficient, sustainable and biologically based cleaning products.