Performance of Co-immobilized Yeast and Glucoamylase in a Fluidized Bed Reactor for Fuel Ethanol Production*

The performance of co-immobilized Saccharomyces cerevisiae and glucoamylase was evaluated in a fluidized bed reactor. Soluble starch and yeast extract were used as feed stocks. The biocatalyst performed well and demonstrated no significant loss of activity or physical integrity during 10 weeks of continuous operation. The reactor was easily operated and required no pH control. No operational problems were encountered from bacterial contaminants even though the reactor was operated under non-sterile conditions over the entire course of experiments. Productivites ranged between 25 to 44 g ethanol L-' h-I. The experiments demonstrated that ethanol inhibition and bed loading had significant effects on bed performance. *The submitted manuscript has been authored by a contractor of the US government under contract DE-AC05-960R22464. Accordingly, the US government retains a nonexclusive, royalty-free license to publish or reproduce the published form of the contribution, or allow others to do so, for US government purposes. ** Author to whom all correspondence should be addressed.