Olayide F. Obidi, Onyiye V. Okoli and Simon C. U. Nwachukwu
Bacterial resistance to conventional paint biocides is widely documented. However, an investigation regarding the preservative potential of carbonaceous soot as a viable alternative is novel. Fresh paint samples (SA, SB and SC) were collected in duplicates from a reputable paint manufacturing company in Lagos, Nigeria. SA was produced with conventional paint biocide, SB and SC were without biocide. All samples were inoculated with 0.032 × 106 cfu/mL of Pseudomonas aeruginosa PA01 (NC 002516.2) previously isolated from spoilt paints and identified by the 16S rDNA analysis. SB was supplemented with crude soot (10 g/L of distilled water) at 200 mL v/v. The preservative efficiency of soot was investigated by monitoring the bacterial population (BP), optical density (OD600nm), viscosity (VIS), the transmittance (TR) and specific gravity (SG) of the samples bi-weekly for 14 weeks. BP increased drastically from 0.032-31.61 × 106 and from 0.032-112.93 × 106 in SA and SC respectively. In contrast, SB increased from 0.032-24.63 × 106 by week 4 but reduced from 24.63 – 10.95 × 106 by week 14. The OD of SA increased from 1.55 to 1.98 by week 8 and decreased to 1.74 by week 14. SB had a decrease from 1.60 to 1.49 by week 4 and increased to 1.63 by week 14, while SC increased from 1.59 to 2.54 by the 14th week.TR increased from 1.80 to 2.30 and 1.25 to 2.20 in SA and SC respectively. In contrast, TR decreased from 2.00 to 1.25 in SB. The viscosity and specific gravity values of all the samples decreased with time with the highest decrease observed in SC and the lowest in SB. The test crude soot showed preservative potential in paints.