Karakterisasi Sifat Fermentasi Beberapa Khamir Hasil Adaptasi Galaktosa Terhadap Hidrolisat Rumput Laut

Abstract

Kappaphycus alvarezii has polysaccharides which consist of galactose as monomer unit. After acid hydrolysis, galactose can be used as carbon and energy source by Pachysolen tannophilus IPBCC Y111149 and Saccharomyces cerevisiae IPBCC Y03545. Yet, the ability of these strains to convert K. alvarezii hydrolysates into bioethanol was low. Therefore, improvement of their fermentation characteristics needs to be pursued. An effort to obtain galactose adapted of P. tannophilus IPBCC Y111149 and S. cerevisiae IPBCC Y03545 and further characterized the fermentation traits of those towards K. alvarezii hydrolysates were carried out in this research. Adaptation was done for 264 times in fresh Yeast Malt Peptone Galactose medium. One cycle of adaptation is about 4 hours. Strains of P. tannophilus adaptation process varied in their galactose fermentation ability, meanwhile S. cerevisiae increased with longer adaptation process. The fermentation characteristics of yeasts in K. alvarezii hydrolysates correlated with their galactose fermentation ability. Fermentation characters of P. tannophilus 88th adaptation towards K. alvarezii hydrolysates was better than wild strain, while S. cerevisiae, except their substrate efficiency, were better than its wild strain. Adaptation process did not modify the shape of P. tannophilus cell, but modified the shape and size of S. cerevisiae cell to become oval-like and bigger.