Bioethanol production from algae requires four major unit operations including: pretreatment, hydrolysis, fermentation and distillation. Because algal biomass has its own characteristics, such as soft organization and high moisture content, the pretreatment of the algae is easier than that of lignocellulosic biomasses. The biological processes has been used for pretreatment of algal materials
The biological pretreatment was done on two biomass samples. The first sample was treated with 1% NaOH for one hr. before treated with Aspergillus niger. While the second biomass sample untreated with 1% NaOH.
The samples un-treated with NaOH, the highest sugar was released on 6th day of saccharification. The Chlorella vulgaris biomass at the synthetic media released the maximum amount of reducing sugars 8.552 g /100 g dried biomass at the 1st day which increased by Aspergillus niger gradually till reaching 19.835 g /100 g dried biomass at the 6th day and the produced bioethanol increased at the synthetic media releasing the maximum amount of bioethanol 3.68 g /100 g dried biomass at the 1st day which increased gradually till reaching 25.20 g /100 g dried biomass at the 5th day. While, The samples treated with 1% NaOH, the maximum amount of reducing sugars at the 1st day was 6.996 g /100 g dried biomass which increased by application of Aspergillus niger gradually till reaching 16.052 g /100 g dried biomass at the 6th day. While the maximum amount of bioethanol at the 1st day 10.95 g /100 g dried biomass which increased gradually till reaching 16.77 g /100 g dried biomass at the 4th day.
Key words: Bioethanol, microalgae, Chlorella vulgaris, Biological method, Aspergillus niger, Saccharomyces cerevisiae.
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