Rhamnolipid biosurfactant production by Pseudomonas aeruginosa strain KVD-HR42 isolated from oil contaminated mangrove sediments

Abstract

Pseudomonas aeruginosa strain KVD-HR42 exhibiting growth and biosurfactant production with 1% molasses as the sole carbon source was isolated from oil contaminated mangrove sediments. Optimization of media conditions involving variations in carbon, nitrogen sources, amino acids, pH, temperature, and NaCl% were evaluated with the aim of increasing biosurfactant productivity and surface tension reduction (STR). The highest biosurfactant production of 4.83 g/L was obtained when cells were grown in mineral salts media (MSM) supplemented with 1% (w/v) molasses, NaNO 3 , and leucine 0.1% (w/v) at 35±2°C at 150 rpm after 48 h. The results obtained from kinetics study indicated that biosurfactant production, E 24 %, and rhamnose concentration were growth associated. However, maximum biosurfactant production occurred in the exponential growth phase and detected an increase in E 24 % and rhamnose concentration. The Fourier transform infrared (FTIR) spectra confirmed the rhamnolipid nature of the biosurfactant. Stability studies revealed the thermostable activity of biosurfactant (110°C for 15 min) and could also withstand wide pH and NaCl ranges. Maximum oil biodegradation of 68% was achieved with 1% waste lubricant oil (WLO). The biosurfactant emulsified various hydrocarbons with varied efficiencies. However maximum E 24 % and E 48 % activity was exhibited with n-hexadecane (69.5 and 40%). The results reveal the potential of strain KVD-HR42 biosurfactant for the bioremediation of petroleum hydrocarbons in mangrove sediments.

Di- and Mono-Rhamnolipids Produced by the Pseudomonas putida PP021 Isolate Significantly Enhance the Degree of Recovery of Heavy Oil from the Romashkino Oil Field (Tatarstan, Russia)

“…Hydroxyl groups identified by symmetric O-H stretching referred to carbohydrate fragments, the region after 1648 cm −1 to 1316 cm −1 corresponded to groups characteristic of carbonyl groups in unsaturated aliphatic carboxylic acids, a weak C=O ester signal at 1724 cm −1 and fan stretching vibration for CH 2 . The observed peaks correspond to the spectra described by other authors for rhamnolipids [48][49][50].…”

Green synthesis of copper ions nanoparticles functionalized with rhamnolipid as potential antibacterial agent for pathogenic bacteria

“…2 shows a wide vibrational peak at 3391 cm −1 , indicating the –OH functional group in rhamnose. In the region of 2920 and 2859 cm −1 , a sharp peak was observed, indicating the presence of the C–H (–CH 2 , –CH 3 ) functional group in the hydrocarbon chain of the rhamnolipids [ 21 ]. In addition, vibration peaks were also observed in the 1711 and 1405 cm −1 regions, indicating the presence of a carbonyl ester functional group (C O).…”

Production and characterization of rhamnolipid biosurfactant from thermophilic Geobacillus stearothermophilus bacterium isolated from Uhud mountain

“…data were found byDeepika et al (2017) andSabarinathan et al (2021). The FTIR profile authenticated that the produced biosurfactant consists of hydrophobic chains that comprise lipids, sugars, and hydrophilic glycolipids.…”