In-situ Growth,Thermodynamic and Kinetic Properties and Optimized Culture of Rhodopseudomonas palustris
【摘要】：How to monitor the dynamic information of in situ growth process of light-required organisms,and explore their regularities and characteristics of thermodynamics and kinetics in their growth and metabolism process, is important to reveal the in situ growth mechanism of microorganisms and optimize their cultivation, meanwhile, is a critical problem to be solved. In this study, the high-precision and high-sensitive photocalorimetry system was used to investigate the effect of different wavelength and light power on the growth and metabolism of Rhodopseudomonas palustris.According to the thermal spectrum curves, thermodynamic parameters of logarithmic growth phase and heat production for different metabolism were calculated. The results showed that:(1) the effect of different wavelength on growth of bacteria was in the following order: green blue white red.The growth performance of bacteria was not increased with the increase of light power under the different power of green light, the optimum condition for growth was 2~6 W/m~2.(2) The thermal spectrum curves were obtained by culturing the bacteria in different conditions(light source: λ=532 nm, light intensity: 2, 4, 6 W/m~2). By analyzing the thermal spectrum curves, the heat produced by growth was Q_4Q_6 Q_2. There were significant differences between 3 light intensities(P 0.001)in the four periods of bacterial growth. The consuming time for each growth phase(lag phase→lag,logarithmic phase→log, stationary phase→sta., decline phase→dec.) was: t_(2 lag)t_(6 lag)t_(4 lag), t_(4 log).t_(6 log).t_(2 log)., t_(2 sta).t_(6 sta).t_(4 sta)., t_(4 dec).t_(6 dec).t_(2 dec).; the thermal power peak was: P_(4 max) P_(6 max) P_(2 max),and t_(2 max) t_(6 max) t_(4 max) t_(2 max).; bacterial growth rate was: k_4 k_6 K_2; the generation time of bacteria was: t_(G2)t_(G4)t_(G6); the optimum condition seems to be 4 W/m~2, since photosynthetic bacteria first entered its logarithmic growth phase and logarithmic growth phase was longest, in addition, bacteria can reach the peak thermal value in the shortest time. The growth rate and generation time of bacteria in logarithmic growth phase were affected by light intensity, logarithmic duration and other factors.(3) Suitable light can keep the growth of bacteria in a good situation by maximum mobilizing the photosynthetic cells. In this experiment, promotive effect on the growth of bacteria at 4 W/m~2 was mainly reflected in lag phase, logarithmic growth phase and stable phase.However, whether it has effect on toxic products in decline phase still needs further study.