Biosurfactant production by a CO2 sequestering Bacillus sp. strain ISTS2

Area of Science:

• Microbiology
• Biotechnology
• Environmental Science

Background:

• Industrial carbon dioxide (CO2) emissions pose environmental challenges.
• Biosurfactants are surface-active agents with diverse applications.
• Microbial CO2 utilization offers a promising avenue for sustainable bioprocesses.

Purpose of the Study:

• To evaluate Bacillus sp. strain ISTS2 for CO2 sequestration and biosurfactant production.
• To characterize the biosurfactant produced by the bacterium.
• To explore the potential of using industrial CO2 as a substrate for microbial processes.

Main Methods:

• Chemostat enrichment of Bacillus sp. strain ISTS2 with sodium bicarbonate.
• Measurement of carbonic anhydrase and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) activity for CO2 sequestration.
• Screening of biosurfactant production using surface tension, interfacial tension, emulsification stability, hydrophobicity, and contact angle measurements.
• Purification of biosurfactant using silica gel column chromatography.
• Characterization of biosurfactant composition using Thin Layer Chromatography (TLC) and Gas Chromatography-Mass Spectrometry (GC-MS).

Main Results:

• Bacillus sp. strain ISTS2 demonstrated CO2 sequestration capabilities.
• The bacterium produced biosurfactants under specific conditions (100 mM NH4HCO3 and 5% CO2).
• The crude biosurfactant was identified as a mixture of lipopeptides and free fatty acids (FA).
• The hydrophobic fraction contained five types of fatty acids with chain lengths from C14 to C19.

Conclusions:

• Bacillus sp. strain ISTS2 is capable of both CO2 sequestration and biosurfactant production.
• The identified biosurfactant has potential applications in various industries.
• This study highlights the potential of Bacillus sp. strain ISTS2 as a cleaner bioprocess for utilizing industrial CO2 as an alternative substrate.