Physiological changes in Rhodococcus ruber S103 immobilized on biobooms using low-cost media enhance stress tolerance and crude oil-degrading activity

Abstract

For economic feasibility, sugarcane molasses (0.5%, w/v) containing K2HPO4 (0.26%, w/v) and mature coconut water, low value byproducts, were used in cultivation of Rhodococcus ruber S103 for inoculum production and immobilization, respectively. Physiological changes of S103 grown in low-cost media, including cell hydrophobicity, saturated/unsaturated ratio of cellular fatty acids and biofilm formation activity, enhanced stress tolerance and crude oil biodegradation in freshwater and even under high salinity (5%, w/v). Biobooms comprised of S103 immobilized on polyurethane foam (PUF) was achieved with high biomass content (1010 colony-forming units g−1 PUF) via a scale-up process in a 5-L modified fluidized-bed bioreactor within 3 days. In a 500-L mesocosm, natural freshwater was spiked with crude oil (72 g or 667 mg g−1 dry biobooms), and a simulated wave was applied. Biobooms could remove 100% of crude oil within only 3 days and simultaneously biodegraded 60% of the adsorbed oil after 7 days when compared to boom control with indigenous bacteria. In addition, biobooms had a long shelf-life (at least 100 days) with high biodegradation activity (85.2 ± 2.3%) after storage in 10% (w/v) skimmed milk at room temperature. This study demonstrates that the low-cost production of biobooms has potential for future commercial bioremediation.

Exploring the Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Production Potential of Total Petroleum Hydrocarbon Degrading Bacteria Using Oily Sludge Waste as Feedstock

“…GC-FID was equipped with an OVI-1 packed column (for determining crude oil degradation) and a Mega-5 capillary column (for examining oily sludge degradation), as well as nitrogen as a carrier gas. From GC chromatograms, % degradation was determined using the following formula: % .25em TPH .25em degradation = Total .25em peak .25em area .25em of .25em test × dilution .25em ( if any ) Total .25em area .25em of .25em control × 100 where “test” means substrate extraction from inoculated medium having 1% crude oil or oily sludge as substrate after incubation and “control” is extraction from uninoculated medium with similar substrate concentration and incubated in identical conditions. − …”

Ways of Long-Term Survival of Hydrocarbon-Oxidizing Bacteria in a New Biocomposite Material—Silanol-Humate Gel

“…In the case of oil contamination, large-scale bioremediation required the development of efficient HOB-based preparations, as well as addressing issues such as the long-term preservation of high viable HOB titer during storage, transportation, and the application of the preparations and their improved introduction into contaminated soil biotopes [ 4 , 5 , 6 ]. HOB storage in an immobilized state on the surface of sorbents or incorporated into polymer gels is a promising approach to these problems [ 7 , 8 ].…”