The biokinetics of glucose metabolism were evaluated in Aeromonas hydrophila during growth in an anaerobic biosystem. After approx 34 h growth, A. hydrophila metabolized 5,000 mg glucose l(-1) into the end-products ethanol, acetate, succinate and formate. The maximum growth rate, mu(m), half saturation coefficients, K-s, microbial yield coefficient, Y, cell mass decay rate coefficient, k(d), and substrate inhibition coefficient, K-si were 0.25 +/- 0.03 h(-1), 118 +/- 31 mg glucose l(-1), 0.12 mu g DNA mg glucose(-1), 0.01 h(-1), and 3,108 +/-1,152 mg glucose l(-1), respectively. These data were used to predict the performance of a continuous growth system with an influent glucose concentration of 5,000 mg l(-1). Results of the analysis suggest that A. hydrophila will metabolize glucose at greater than 95% efficiency when hydraulic retention times ( HRTs) exceed 7 h, whereas the culture is at risk of washing out at an HRT of 6.7 h.