Abstract

Issatchenkia orientalis No. SF9-246 cell showed both melanoidin (MP) adsorption and degradation abilities and its MP-adsorption yield was reduced by acclimatization with medium containing MP. The living cell showed the MP-adsorption ability of 15%; higher than the autoclaved cell (dead cell). The MP-adsorption ability of the deteriorated cell (MP-adsorbed cell) was recovered by washing with 0.1 mol L^-1 H₂SO₄ solution. Un-expectantly, the MP-adsorption capacity of the deteriorated cell was about 100 to 150% increased after washing with 0.1 mol L^-1 H₂SO₄ solution. Also, the strain showed the highest biomass production yield of 43.6±2.5 g L^-1 in the medium containing MP within 7 days cultivation and the crude protein content of the biomass was 36.38±1.12%. In addition, the strain produced intracellular glutathione S-transferase enzymes types Y-1 and Y-2 (GST Y-1 and GST Y-2) and GST Y-1 production was induced by MP. 

Key words:  Adsorption, decolorization, Issatchenkia orientalis, melanoidin, molasses wastewater.

Abbreviation

AS, Activated sludge system; BOD₅, biochemical oxygen demand;COD, chemical oxygen demand; GST, glutathioneS-transferase; MP, melanoidin pigment; MWW, molasses wastewater, stillage; MYGPA, malt extract-yeast extract-glucose-peptone agar; MYGPA-MP, malt extract-yeast extract-glucose-peptone agar containing MP; MYGPB, malt extract-yeast extract-glucose-peptone broth; MYGPB-MP, malt extract-yeast extract-glucose-peptone broth containing MP; PCR, polymerase chain reaction;  SDS, sodium dodecyl sulfated; SCP, single cell protein; SWW, synthetic wastewater; SWW-MP, synthetic wastewater containing MP; TEM, transmission electron-microscope; U-MWW, untreated molasses wastewater.