标题：Influence of light wavelengths, light intensity, temperature, and pH on biosynthesis of extracellular and intracellular pigment and biomass of Pseudomonasaeruginosa NR1
摘要：AbstractThe purpose of the present study was to check whether the light is an inducing agent or not for the intracellular and extracellular pigment production byPseudomonas aeruginosa NR1? Is the produced pigment a photoprotective in nature? The aim of the present research study was to evaluate the influence of different light wavelengths, light intensity, temperature, and pH on biomass and intracellular and extracellular pigment production. A strain ofPseudomonasthat was thermoalkalophilic and produces red non-diffusible intracellular and green-diffusible extracellular pigment was isolated, until now no one has reported this type of strain. For determining the effect of different light wavelengths, we introduced and designed a novel ‘selective light wavelength method’, which gave us better results than previously used glass paper wrapping method. Extracellular pigment production was found maximum under darkness, red and blue light wavelengths. Same results were obtained in glass paper wrapping method, but the concentration of pigment produced by bacteria was greater in our method which suggests us that the ‘selective light wavelength method’ is better (for pigment yield) between these methods.The outcome of this study refutes the photo protective role of extracellular pigment, claimed by many researchers. Red and light wavelength was found to suppress the intracellular pigment production. Extracellular pigment production byPseudomonas aeruginosa NR1was maximum in darkness with 4.042 ± 0.03 OD/mL and minimum in green light (Glass paper plates (GPP), 2.151 ± 0.24 OD/mL; Selective lamp plates (SLP), 2.232 ± 0.28 OD/mL). Maximum intracellular pigment (SLP, 4.672 ± 0.15 OD/mL; GPP, 4.395 ± 0.03 OD/mL) and biomass concentrations (Selective lamp method-830 ± 5.7 µg/0.01 L; Glass paper method, 810 ± 2.88 µg/0.01 L) were achieved under yellow light wavelength. Minimum intracellular pigment yield (GPP, 2.124 ± 0.01 OD/mL; SLP, 2.252 ± 0.0 OD/mL and biomass yield (Glass paper method, 363.3 ± 3.33 µg/0.01 L; selective lamp method-385 ± 2.88 µg/0.01 L) was recorded under red light wavelength. Direct relationship was observed between biomass production and intracellular pigment production. Maximum extracellular (3.548 ± 2.2 OD/mL) and intracellular pigment (3.856 ± 0.02 OD/mL) and biomass concentration (800 ± 1.44 µg/100 mL) were observed when pH was 7. The intracellular pigment concentration (3.698 ± 0.01 OD/ml) and biomass production (656 ± 3.05 µg/ml) were maximal at a temperature of 30 °C. The maximum concentration of extracellular pigment was recorded at 35 °C (3.924 ± 0.04 OD/ml).
