Improvement of Industrially Relevant Biological Activities in Mucoromycotina Fungi

Mucoromycotina contain several biotechnologically important fungi, primarily in the orders Mucorales and Mortierellales, which are considered as excellent producers of lipases and proteases, organic acids, alcohol, carotenoids and polyunsaturated fatty acids. Here, we overview gene expression and metabolic engineering studies performed to improve industrially relevant activities in different Mucoromycotina fungi in the past decade. Genetic transformation methods used to manipulate these fungi, especially Rhizopus oryzae, Mucor circinelloides and Mortierella alpina, and promoters used successfully to express genes in them will be reviewed. Concerning the improvement of production of hydrolytic enzymes special attention has been paid to the heterologous expression of lipases, which are among the best characterized enzymes in these fungi. Main achievements in the improvement of lactic acid and fumaric acid production by Rhizopus enzymes have also been summarized. Expression of endogenous and exogenous terpenoid and carotenoid biosynthetic genes to enhance and modify the carotene production of Mucor circinelloides has been detailed. Finally, homologous and heterologous expression of Mucoromycotina fatty acid desaturases and elongases in fungi and plants has been overviewed with special attention to the production of arachidonic acid and γ-linolenic acid.