Continuous ethanol production by a flocculating strain of Kluyveromyces marxianus: bioreactor performance

A flocculating strain of Kluyveromyces marxianus was used for alcoholic fermentation in a continuous bioreactor working with zero residual concentration in effluent. Specific kinetic parameters were improved by increasing dilution rate, which is similar to results obtained with ultrafiltration systems. Specific biomass accumulation rate had always a value greater than 92.5% of specific biomass growth rate and was independent of the dilution rate. Productivity is shown to be 12.5 times greater than in conventional continuous operation and is directly proportional to dilution rate. Maximum biomass concentration also presents a linear relationship with dilution rate. The largest obtained biomass concentration is 8 times greater than in a conventional continuous fermentor.