Engineering the morphology and metabolism of pH tolerant Ustilago cynodontis for efficient itaconic acid production.

Engineering the morphology and metabolism of pH tolerant Ustilago cynodontis for efficient itaconic acid production.

Metab Eng. 2019 May 12;:

Authors: Tehrani HH, Tharmasothirajan A, Track E, Blank LM, Wierckx N

Abstract
Besides Aspergillus terreus and Ustilago maydis, Ustilago cynodontis is also known as a natural itaconate producer. U. cynodontis was reported as one of the best itaconate producing species in the family of the Ustilaginaceae, featuring a relatively high pH tolerance in comparison to other smut fungi. However, in contrast to U. maydis, it readily displays filamentous growth under sub-optimal growth conditions. In this study, U. cynodontis is established as efficient pH-tolerant itaconic acid producer through a combination of morphological and metabolic engineering. Deletions of the genes ras2, fuz7, and ubc3 abolished the filamentous growth of U. cynodontis, leading to a stable yeast-like growth under a range of stress-inducing conditions. The yeast-like morphology was also maintained in a pulsed fed batch production of 21 g L-1 itaconic acid and 9.3 g L-1 (S)-2-hydroxyparaconate at a pH of 3.8. The genetic and metabolic basis of itaconic acid production in U. cynodontis was characterized through comparative genomics and gene deletion studies. A hyper-producer strain was metabolically engineered using this knowledge resulting in a 6.5-fold improvement of titer.

PMID: 31091468 [PubMed – as supplied by publisher]

Source: Industry