The continuous production of ethanol from beet molasses by Ca-alginate immobilized Saccharomyces cerevisiae in a packed-bed bioreactor was investigated. At higher substrate concentrations, substrate was recirculated through the packedbed bioreactor to increase yields and to decrease residual sugar content. | Turk J Biol 25 (2001) 265-275 © TÜB‹TAK Production of Ethanol from Beet Molasses by Ca-Alginate Immobilized Yeast Cells in a Packed-Bed Bioreactor Yekta GÖKSUNGUR, Nefle ZORLU Ege University, Faculty of Engineering, Department of Food Engineering, ‹zmir - TURKEY Received: Abstract: The continuous production of ethanol from beet molasses by Ca-alginate immobilized Saccharomyces cerevisiae in a packed-bed bioreactor was investigated. The temperature was maintained at 30°C and the dilution rate was h-1. Maximum ethanol (), theoretical yield () and volumetric productivity ( gl-1h-1) were obtained from the beet molasses medium containing total sugar with mm diameter beads prepared from 2% (w/v) sodium alginate solution. At higher substrate concentrations, substrate was recirculated through the packedbed bioreactor to increase yields and to decrease residual sugar content. The bioreactor system was operated at a constant dilution rate of h-1 for 25 days without loss of original fermentation capacity. Compared to packed-bed bioreactor, lower ethanol concentration (), theoretical yield () and productivity ( gl-1h-1 ) were obtained in the continuous stirred bioreactor. Key Words: ethanol, beet molasses, calcium alginate, immobilization, packed-bed bioreactor Dolgulu Yatak Biyoreaktörde Ca-Aljinatta Tutuklanm›fl Maya Hücreleri ile Pancar Melas›ndan Etil Alkol Üretimi Özet: Bu çal›flmada dolgulu yatak biyoreaktör kullan›larak Ca-aljinatta tutuklanm›fl Saccharomyces cerevisiae hücreleri ile pancar melas›ndan sürekli yöntemde etil alkol üretimi araflt›r›lm›flt›r. Çal›flma s›cakl›¤›n›n 30°C, kullan›lan seyreltme h›z›n›n h-1 oldu¤u çal›flmada en yüksek etil alkol (), teorik verim () ve hacimsel verimlilik ( gl-1h-1) de¤erleri % bafllang›ç fleker konsantrasyonu içeren ortamda, %2 Na-aljinattan üretilen, mm çap›ndaki boncuklarla elde edilmifltir. Daha yüksek substrat .
