Optimization of low-cost biosurfactant production from agricultural residues through response surface methodology

Abstract

Biosurfactants are surface-active compounds capable of reducing surface tension and interfacial tension. Biosurfactants are produced by various microorganisms. They are promising replacements for chemical surfactants because of biodegradability, nontoxicity, and their ability to be produced from renewable sources. However, a major obstacle in producing biosurfactants at the industrial level is the lack of cost-effectiveness. In the present study, by using corn steep liquor (CSL) as a low-cost agricultural waste, not only is the production cost reduced but a higher production yield is also achieved. Moreover, a response surface methodology (RSM) approach through the Box-Behnken method was applied to optimize the biosurfactant production level. The results found that biosurfactant production was improved around 2.3 times at optimum condition when the CSL was at a concentration of 1.88 mL/L and yeast extract was reduced to 25 times less than what was used in a basic soybean oil medium (SOM). The predicted and experimental values of responses were in reasonable agreement with each other (Pred-R(2) = 0.86 and adj-R(2) = 0.94). Optimization led to a drop in raw material price per unit of biosurfactant from $47 to $12/kg. Moreover, the biosurfactant product at a concentration of 84 mg/L could lower the surface tension of twice-distilled water from 72 mN/m to less than 28 mN/m and emulsify an equal volume of kerosene by an emulsification index of (E24) 68% in a two-phase mixture. These capabilities made these biosurfactants applicable in microbial enhanced oil recovery (MEOR), hydrocarbon remediation, and all other petroleum industry surfactant applications.

Biochemical and molecular identification of newly isolated pigmented bacterium and improved production of biosurfactant

“…Several studies described the of biosurfactants production optimization by culture media of low cost associated with industrial residue as insoluble substrates (Silva et al, 2010;Joshi et al, 2013;Ebadipour et al, 2016).…”

Two schemes for production of biosurfactant from Pseudomonas aeruginosa MR01: Applying residues from soybean oil industry and silica sol–gel immobilized cells

“…Biosurfactant pellets were harvested by centrifugation at 18000 ×g at 4°C for 20 min and solvent extracted with ethyl acetate. Solvent was removed by evaporation and the extract was then weighed to determine the biosurfactant concentration [28].…”

“…In the present study, we examined the immobilization of Pseudomonas aeruginosa MR01 in sol-gel silica matrices and its application for biosurfactant production. This strain previously demonstrated good potential to produce biosurfactant under controlled conditions [1,27,28] and, therefore, may be considered a suitable candidate for this purpose. Herein, silica gel matrixes were synthesized with TEOS as the precursor and used for entrapping the P. aeruginosa MR01 in the presence of high molar ratio of water to alkoxy silicate.…”

Biodegradation of Cyanide under Alkaline Conditions by a Strain of Pseudomonas Putida Isolated from Gold Mine Soil and Optimization of Process Variables through Response Surface Methodology (RSM)

“…The diagnostic plot (Fig. 6) was also used for estimating the adequacy of the regression model [37]. Tendencies in linear regression in the graph showed a satisfactory correlation between predicted and experimental values.…”