Abstract: A galactosamine producing-strain YR06 was isolated from the sludge where the dead fish and crab was decomposed in Dongying Yellow River estuary wetland. Based on morphology, physiological and biochemical characteristics as well as the 16S rDNA gene sequence, strain YR06 was identified as Aeromonas hydrophila. Optimization of YR06 fermentation conditions was studied via single factor and orthogonal test design. The optimum fermentations conditions were showed as followed：fructose 10 g/L, urea 15 g/L, Na₂HPO₄ 15 g/L, CaCl₂ 22.2 g/L, MgSO₄ 0.18 g/L, KH₂PO ₄ 5 g/L；initial pH6.5, fermentation holding 60 mL/250 mL, fermentation temperature 33℃. The yeild of galactosamine achieved 128 mg/L after the optimization.

Key words: Aeromonas hydrophila, Galactosamine, Screening, Identification, Cultural conditions