This study aimed to evaluate the synergism of cellulases and amylolytic enzymes in the hydrolysis of microalgal carbohydrates for bioethanol production. The effect of β‐glucosidase on the hydrolysis of algal cellulose, and the comparison between the effect of the addition of α‐amylase and amyloglucosidase separately or together on the hydrolysis of algal starch, have not been described previously. Results showed that β‐glucosidases promoted the enzymatic hydrolysis of algal cellulose as a result of the increase in the glucose production rate and the decrease in the inhibition by cellobiose. It was also beneficial to carry out the hydrolysis of algal starch using the mixture of α‐amylase and amyloglucosidase. The results obtained revealed that, in enzymatic hydrolysis experiments, simultaneous treatment with Celluclast 1.5 L, β‐glucosidase, α‐amylase, and amyloglucosidase was a promising strategy to reduce the hydrolysis time required to achieve a higher yield of glucose. Subsequently, fermentation of enzymatic hydrolysates of microalgae using Saccharomyces cerevisiae showed a yield of 0.126 g ethanol / g dried algae. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd