The role of amylase in bioethanol production: advances in amylase-producing strains using CRISPR/Cas9 Technology

• Amylase is important in bioethanol production. • Various sources and types of amylases are discussed. • Physicochemical factors and CRISPR/Cas9 used to increase amylase yield are emphasized. • Starch-containing wastes are a good source for bioethanol production. • Hydrolysis of starch using amylase is a key step in bioethanol production. Lignocellulosic biomass derived from food waste, microalgae, and agroresidues is key in the circular bioeconomy, promoting eco-friendly bioethanol production while addressing waste management challenges. This paper aimed to comprehensively review the role of amylases secreted from different strains in bioethanol production. The sources and optimizing factors critical for effective starch breakdown are discussed. Amylase, derived from various organisms, constitutes an essential enzyme and facilitates starch hydrolysis into fermentable sugars like glucose, a key step in bioethanol production. However, its activity depends on factors such as pH, temperature, incubation time, and the substrates used, necessitating optimization for efficient starch degradation. Moreover, the review also explores strategies to engineer amylase-producing strains with enhanced amylase production capabilities using an advanced clustered regularly interspaced short palindromic repeat (CRISPR/Cas9)-based gene editing technology. Further research is crucial to identify novel amylase-producing strains from different environments, including from extremophiles, characterize their enzymes, and leverage tools like CRISPR/Cas9-mediated genome editing in microorganisms, and leverage these advancements to ensure sustainable bioethanol production.