Optimization of Inocula Conditions for Enhanced Biosurfactant Production by Bacillus subtilis SPB1, in Submerged Culture, Using Box–Behnken Design

Abstract

The inoculum age and density can influence considerably the production yield and cost of the fermentation process. Some literature studies report the use of two-stage inocula to enhance metabolite production. In the present study, optimization studies were done in order to define the best inocula conditions supporting a maximum biosurfactant production by Bacillus subtilis SPB1. Hence, by adjusting the levels of the two-stage inocula strategy, lipopeptide production was effectively enhanced to almost 3.4 g/l as estimated gravimetrically. The new defined parameters were as follows; a first inoculum age of 23 h followed by a second inoculum age and size of 4 h and 0.01, respectively. Thereby, we note an improved production as compared to the production yield described under non-optimized inocula conditions reported in our previous work.

Response Surface Methodology for Optimizing the Production of Biosurfactant by Candida tropicalis on Industrial Waste Substrates

“…The higher number of cells may increase the competition for the nutrients for cell maintenance rather than the production of biosurfactant (Ghribi and Ellouze-Chaabouni, 2011; Onwosi and Odibo, 2013; Nalini and Parthasarathi, 2014). Inoculum size has demonstrated high influence on biosurfactant production in previous studies and can have a definite effect on economics of a microbial process (Mnif et al, 2013; Onwosi and Odibo, 2013). The CCRD conducted by Lima and Souza (2014) showed that the inoculum concentration was the factor that had the greatest effect on biosurfactant production by Bacillus subtilis PC, providing the best surface tension values of the 32 mNm −1 .…”

Isolation and characterization of a biosurfactant‐producing Fusarium sp. BS‐8 from oil contaminated soil

“…The metabolite accumulation and cell growth were also highly influenced by composition of the medium such as carbon and nitrogen sources, C:N ratio and other factors that affect the growth . It is obvious that the medium components play critical role in improved biosynthesis of the metabolites, thus optimizing cultural conditions could enhance the yield of biosurfactants …”

“…Thus, the oil contaminated sites are envisaged as enriched source of biosurfactant‐producing microorganisms . So far, most of research in the field of biosurfactants has been carried out using bacteria and yeasts, however, biosurfactants from different filamentous fungi have also been reported by a few scientists . Unlike other oleaginous microbes, filamentous fungi are considered as dynamic mini‐eukaryotic biofactories for production of many industrially important biotechnological products, including commercial enzymes, organic acids, alkaloids, plant growth regulators, antibiotics, polysaccharides, and pigments .…”

Statistical Design, a Powerful Tool for Optimizing Biosurfactant Production: A Review

“…A B. subtilis strain lipopeptide production was optimized to 3.4 gL −1 using a BBD [39]. Primary inoculum age, secondary seed culture age, and size were the factors evaluated.…”

“…A lower initial cell density also increased Bs productivity. This was explained by the fact that in the case of sporulating bacteria like B. subtilis, less and younger biomass would lengthen the exponential phase where the Bs can be produced; since once the stationary phase is reached sporulation processes are induced [39].…”