Brown algae contain alginate [3–38% on a dry weight basis (14)] as major components, but microorganisms rarely convert the alginate to ethanol.
To overcome this problem, genetically engineered microorganisms were developed to convert alginate to ethanol, and the ethanol concentration in the fermentation culture was observed at 13 g/l (16.5 ml/l) utilizing alginate alone as a carbon source (15) and 47 ml/l utilizing whole components of Saccharina japonica (kombu) as carbon sources (16).