Valorization of frying oil waste for biodetergent production using Serratia marcescens N2 and gamma irradiation assisted biorecovery

Abstract

Background The complexity, toxicity and abundance of frying oil waste (FOW) render it difficult to be degraded biologically. The aim of the present work was to valorize FOW and investigate the potential use of the produced biosurfactant by Serratia marcescens N2 (Whole Genome sequencing accession ID SPSG00000000) as a biodetergent. Results Serratia marcescens N2 demonstrated efficient valorization of FOW, using 1% peptone, 20% FOW and 8% inoculum size. Gene annotation showed the presence of serrawettin synthetase indicating that the produced biosurfactant was serrawettin. Zeta potential and Fourier Transform Infrared (FTIR) spectroscopy indicate that the biosurfactant produced was a negatively charged lipopeptide. The biosurfactant reduced the surface tension of water from 72 to 25.7 mN/m; its emulsification index was 90%. The valorization started after 1 h of incubation and reached a maximum of 83.3%. Gamma radiation was used to increase the biosurfactant yield from 9.4 to 19.2 g/L for non-irradiated and 1000 Gy irradiated cultures, respectively. It was noted that the biorecovery took place immediately as opposed to overnight storage required in conventional biosurfactant recovery. Both chemical and functional characteristics of the radiation induced biosurfactant did not change at low doses. The produced biosurfactant was used to wash oil stain; the highest detergency reached was 87% at 60 °C under stirring conditions for 500 Gy gamma assisted biorecovery. Skin irritation tests performed on experimental mice showed no inflammation. Conclusion This study was able to obtain a skin friendly effective biodetergent from low worth FOW using Serratia marcescens N2 with 83% efficient valorization using only peptone in the growth media unlike previous studies using complex media. Gamma radiation was for the first time experimented to assist biosurfactant recovery and doubling the yield without affecting the efficiency.

Sequential electron beam and bioflocculation for treatment of textile nanodyes

“…The preliminary results showed no decolorization when using the bacterial culture. This may be due to the vivid red color of Serratia marcescens N2 culture and culture filtrate 26 that can interfere with the spectral analysis of the red nanodye under study.…”

“…Biosurfactant was produced as described in a previous study. 26 Serratia marcescens N2 was cultivated in 20% fish frying oil, 1% peptone and an inoculum concentration of 8% at 25 °C for 13 days.…”

“…They are reported to be produced by different bacteria, for example; Pseudomonas taiwanensis , 22 Rhodococcus erythropolis , 23 Kurthia gibsonii , 24 Pseudomoas aeruginosa , 25 Serratia marcescens N2 (ref. 26 ) and Bacillus sp. 27 Their use in bioremediation was successfully reported for the removal of heavy metals and polyaromatic hydrocarbons, dyes 28 and crude oil.…”