Production of poly-d-3-hydroxybutyric acid from carbon dioxide by a two-stage culture method employing Alcaligenes eutrophus ATCC 17697T

Control of acetic acid concentration by pH-stat continuous substrate feeding in heterotrophic culture phase of two-stage cultivation ofAlcaligenes eutrophus for production of P(3HB) from CO2, H2, and O2 under non-explosive conditions

“…Concentrations of biomass and P(3HB) increased to 22.9 and 12.6 g и dm −3 , respectively after 83 h of autotrophic cultivation. However, the concentration and productivity of P(3HB) obtained in this culture experiment were lower than in the previous study for autotrophic P(3HB) production (Ishizaki and Tanaka, 1991;Taga et al, 1997;Tanaka and Ishizaki, 1994;Tanaka et al, 1995a). This was thought to be due to the inhibitory effect of acetic acid on the enzymes relating to hydrogen oxidation and carbon dioxide fixation under autotrophic condition.…”

“…Hence, we developed a new culture method in order to obtain a high P(3HB) concentration with a conventional fermenter design under safe culture conditions. The concept of the culture method is to have a heterotrophic culture stage with organic carbon source for cell growth followed by an autotrophic culture stage for P(3HB) accumulation (Tanaka and Ishizaki, 1994). In the previous study, 21.6 g и dm −3 of P(3HB) was produced from CO 2 by this culture method using 10 g и dm −3 fructose as carbon source in the heterotrophic stage.…”

Effects of rheological change by addition of carboxymethylcellulose in culture media of an air-lift fermentor on poly-D-3-hydroxybutyric acid productivity in autotrophic culture of hydrogen-oxidizing bacterium, Alcaligenes eutrophus

“…The P(3HB) concentrations obtained in our study using the air-lift fermentor under the oxygen-limited condition were higher than those of previous reports for autotrophic P(3HB) production using the conventional stirred-tank fermentor. (Ishizaka and Tanaka, 1991;Morinaga et al, 1978;Siegel and Ollis, 1984;Tanaka and Ishizaki, 1994;Vollbrecht et al, 1979). The effects of surface-active reagents on K L a value are unpredictable (Pirt, 1975).…”

“…The cells were cultivated by a two-stage method (Tanaka and Ishizaki, 1994). First, one loop of the stock culture was inoculated into 5 mL of nutrient-rich medium in a test tube and incubated at 30°C for 12 h with shaking.…”

“…The result is a serious decrease in P(3HB) productivity and final P(3HB) concentration. To solve this problem of decrease in P(3HB) productivity in autotrophic fermentation of hydrogen-oxidizing bacterium, we developed a two-stage culture method consisting of a heterotrophic culture for cell growth and an autotrophic culture for P(3HB) accumulation from CO 2 , with concomitant feeding of substrate-gas mixture, whose O 2 concentration was lower than 6.9% (Tanaka and Ishizaki, 1994). However, further improvement of productivity and reduction in process cost are essential for practical application of P(3HB) production from CO 2 .…”