Rapid quantification of a microbial surfactant by a simple turbidometric method

Area of Science:

• Microbiology
• Biotechnology
• Analytical Chemistry

Background:

• Accurate quantification of microbial biosurfactants is crucial but hindered by a lack of rapid, efficient methods.
• Existing techniques are often time-consuming and complex, limiting high-throughput analysis of biosurfactant production.

Purpose of the Study:

• To develop a simple, rapid, and accurate turbidometric method for quantifying crude biosurfactants.
• To validate the method's efficacy across different bacterial strains and fermentation conditions.

Main Methods:

• A novel turbidometric assay based on biosurfactant insolubility at low pH was employed.
• Linear correlations were established between turbidity and crude biosurfactant concentration (1-10 g L⁻¹).
• Substrate-specific equations (SSE) and generalized equations (GE) were developed for prediction.

Main Results:

• A strong linear correlation (R² > 0.99) was observed between biosurfactant concentration and turbidity for Bacillus sp.
• The developed equations (SSE and GE) accurately predicted crude biosurfactant yields in fermentation experiments.
• Similar linear correlations were confirmed for biosurfactants from Bacillus circulans and Pseudomonas sp.

Conclusions:

• The proposed turbidometric method offers a fast, inexpensive, and accurate approach for quantifying crude biosurfactants.
• This method is applicable to biosurfactants produced by diverse bacterial species.
• It significantly simplifies the assessment of microbial biosurfactant production.