Abstract
Algae are considered as a good substrate for bioethanol production. This study was carried out to evaluate the potential chemical and biological hydrolysis of the macrogreen alga Ulva fasciata and the microgreen alga Chlorella vulgaris to pretreatment of cell wall and sugar production. Different concentrations of reduced sugar extracted from U. faciata was studied to obtain the maximum amount of bioethanol. Saccharomyces cerevisiae SH02, Pseudomonas sp. SH03, were used to determine the best microorganisms that affect in fermentation process and hence the production of bioethanol. U. fasciata contains maximum amount of sugar. Chemical hydrolysis is the best methods for pretreatment of algae. S. cerevisiae SH02 was the best microorganisms for fermentation process with sugar obtained from U. faciata by chemical hydrolysis. The highest ethanol production by S. cerevisiae SH02 was 40% with 5% sugar concentration that produced by acid hydrolysis and with increasing sugar ratio ethanol production decrease. The highest ethanol yield with Pseudomonas sp. SH03 was 22% obtained by fermentation of 5% algal sugar.