RESUMO
Acetobacter living cells were immobilized by adsorption onto a ceramic support. The effects of acetic acid inhibition have been studied in a fixed-bed pulsed-flow reactor. Provided that sufficient oxygen was available, the concentration of acetic acid was found to be independent of the flow rate. Damped oscillations of acetic acid concentration were observed after step changes in dilution rate. The theoretical model developed from steady-state data was successful in predicting the experimental dynamic behavior of the reactor.
RESUMO
Microbes capable of degrading organic wastes (sewage) are densely packed (immobilized) within the pores of controlled-pore ceramics. When the ceramic displays the optimum pore range for the reproduction of these microbes, the minimum volume for a very efficient reactor is required. A two-stage, anaerobic, immobilized microbe reactor has been designed, and laboratoryscale units have been constructed. A few of these units have been operated continuously for two years. These reactors were designed for the efficent conversion of carbon to methane in biodegradable molecules and for the effective transfer of that gas. The reactors were operated at 20, 30, and 40 degrees C at residence times of 2-5.5 h. The total chemical oxygen demand (COD) of the sewage varied from 800-2600 mg/L. The resulting gas contained greater than 90% methane and less than 5% CO(2). Approximately 32-54% of the influent total carbon was recovered as methane. The reduction in COD varied from 63 to 89%.
RESUMO
The feasibility of using columnar reactors containing immobilized microorganisms for the rapid estimation of BOD was demonstrated in this study. Dilutions of three types of industrial effluents were tested by the BOD5 test and by this experimental system. A high degree of correlation (r = 0.98) was observed between results of the two tests. The mean standard error of estimation of the experimental system was 11%.
RESUMO
Media containing the fluorogenic compound 8-anilino-1-naphthalene sulfonic acid may be used to discriminate between gram-positive and gram-negative bacteria and to differentiate between various species of bacteria. Fluorescent light emitted from colonies of gram-negative bacteria on 8-anilino-1-naphthalene sulfonic acid-containing agar was visually more intense than that on gram-positive bacteria. The emitted light from the gram-negative bacteria differed in wave-lengths from that of light emitted by colonies of gram-positive bacteria. The fluorescent intensity of colonies on complete 8-anilino-1-napthalene sulfonic acid agar supplemented with 1% of single substrates varied depending on the bacterial species, thus allowing the development of profiles used to identify 12 different species.
