Strain engineering of Aspergillus species for industrial enzymes bioproduction: a comprehensive review

Filamentous fungi of the genus Aspergillus, because of their exceptional secretory capacity and metabolic versatility have been extensively applied in traditional food fermentation and industrial biotechnology for production of diverse bioproducts. Their history of domestication and industrial application has enabled major progress in enzyme production; however, challenges associated with the filamentous growth and strain engineering for future biomanufacturing development still remain. This review summarizes the advances across the spectrum of strain-improvement methodologies, from classical mutagenesis, protoplast fusion, genome shuffling, and adaptive laboratory evolution to the modern era of CRISPR enabled genome editing, synthetic biology, and systems-level metabolic engineering. Previous reviews have primarily focused on individual Aspergillus species, specific industrial products or particular strain improvement approaches. In this review, we provide a comprehensive overview of classical and modern strain engineering technologies and industrial scale up across a wide range of Aspergillus species for industrial enzyme production. In particular, emerging non-GMO evolution tools such as atmospheric and room temperature plasma (ARTP) mutagenesis, and modern molecular biotechnology coupled with microdroplet-based ultrahigh-throughput screening, now allow the researchers to generate and screen a large number of Aspergillus species mutants with single-cell precision. The discovery of high-performance strains with enhanced secretion, stress tolerance, substrate utilization, and favorable enzymatic profiles for food and bioprocessing applications has been accelerated by the strain innovations. Collectively, these advances establish A. oryzae and the related species as increasingly reliable, scalable, and programmable hosts that can meet the biomanufacturing requirements of future circular and sustainable bioeconomies.