maliheh najafi

Microorganisms are more important than other sources in dye production because microorganisms have advantages such as rapid growth, higher yields, and easier extraction. Natural pigments are healthier than chemical types and their use is useful in various industries. The aim of this study was to isolate and extract the pyocyanin pigment from Pseudomonas aeruginosa isolates in order to preparation of colored paper and candle.

In this study, sampling was performed from different hospital environments in order to isolate P. aeruginosa. Environmental isolates of P. aeruginosa were identified using morphological features and differential biochemical methods. Confirmatory identification was performed by tracing the pbo1 gene using colony PCR. After extracting pyocyanin pigment with chloroform, finally, the produced pyocyanin was used to prepare colored paper and candle and the optical stability of pyocyanin was investigated.

From 43 environmental samples collected, 15 isolates of P. aeruginosa were identified and confirmed by molecular method. The mean of optical absorption (OD520) of pyocyanin after extraction was 0.488. Staining of paper and candle with the extracted pyocyanin was successful and the optical stability of pyocyanin was favorable.

Due to the rapid growth of bacteria and the possibility of its mass production in a short time and based on the results of this study, bacterial pigments can be used in various industries, including paper industry, and replaced by chemical dyes.

Among the volatile organic compounds, benzene, toluene, ethylbenzene and xylene compounds (BTEX) are important as air pollutants that have harmful effect for health even at very low concentrations. The main source of these compounds is the exhaust gases from vehicles exhaust. The purpose of this study was to measure BTEX compounds in outdoor and indoor environment of 4 high schools located in two districts of Isfahan and Chadegan city. Samples of air from inside and outside the schools were collected by individual sampling pumps using active carbon tubes. Then BTEX compounds were extracted by solvent CS2 and measured by mass spectrometric gas chromatography (GC-MS). Findings: The average concentration of BTEX compounds in Isfahan city was higher than Chadegan. Also, the concentration of BTEX compounds in Isfahan region 2 (Imam Hossein Square) was higher than Zone 1 (Chahar Bagh Khaju) and the highest and lowest concentrations among the BTEX components were respectively in relation to toluene and ethylbenzene. There was not significant difference between Indoor/Outdoor ratio in two regions. There was no significant relationship between the indoor and outdoor concentrations of BTEX compounds in two cities and two regions, which shows that the indoor environment is contaminated by internal resources. Based on the results, the city of Isfahan was more polluted then Chadegan. Also, region 2 in Isfahan was more polluted than region 1. So that the pollution is more related to external sources such as traffic. Keywords

Nanoparticles with the different sizes, surfaces and chemical characteristics can have different applications. Pseudomonas aeruginosa is an opportunistic bacterium that has the ability to produce pigment. The aim of this study was to investigate the effect of zinc oxide (ZnO) nanoparticles on pigment production of clinical isolates of Pseudomonas aeruginosa.
In this description cross-sectional study, 15 clinical isolates of Pseudomonas aeruginosa were collected from hospitals in Mashhad. Bacteria were identified using biochemical tests and polymerase chain reaction (PCR) by specific primers of exoA gene. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of zinc oxide nanoparticles (diameter of 4-7 nm) were determined by agar dilution method. Glycerol- alanine (GA) medium containing different concentrations (0, 20, 40 and 60 mg/ml) of nanoparticles were used for investigation of the effect of ZnO nanoparticles on pigment production. The pigment was extracted by adding chloroform.
Findings: All clinical isolates were identified by biochemical experiments as P. aeruginosa and exoA gene was detected in all bacteria. The average MIC and MBC of ZnO nanoparticles were 60 mg/ml and 70 mg/ml, respectively. All isolates were examined and compared for pyocyanin pigment production. The pigment production was significantly reduced with increasing concentrations the ZnO nanoparticles (p Discussion & Zinc oxide nanoparticles had inhibitory effect on bacteria and pigment production. Pigment production decreased with increasing concentrations of nanoparticles. ZnO nanoparticles could be used in prevention or helping to treat P. aeruginosa infections.