Exploiting Issatchenkia orientalis SD108 for succinic acid production

Abstract

Background: Recent advances in synthesizing valuable chemicals such as organic acids from low-cost renewable biomass through microbial fermentation have attracted great attention. However, the toxicity of organic acids presents a key challenge to the development of an economically viable fermentation process. Therefore, a platform organism that not only produces organic acids but also tolerates the associated toxicity is highly desirable. Results: Here we report the discovery, characterization, and engineering of a yeast strain, Issatchenkia orientalis SD108, that is tolerant to low pH and high concentration of organic acids. This strain demonstrated a higher tolerance compared to I. orientalis ATCC 24210 and Classic Distiller's Turbo yeast. In order to explore SD108 as a potential platform organism for organic acid production, we determined its draft genome sequence and use the sequencing information to guide pathway design. As proof of concept, an engineered four-gene expression cassette related to the reductive TCA cycle was assembled and integrated into the genome of a uracil auxotroph of SD108. The resulting strain was able to produce succinic acid with a titer of 11.63 g/L, yield of 0.12 g/g, and productivity of 0.11 g/L · h in batch cultures using shake flasks.

Comprehending the influence of critical cultivation parameters on the oleaginous behaviour of potent rotten fruit yeast isolates

“…) and succinic acid production (Xiao et al . ). However, in terms of oleaginicity, this yeast is a newly recognized one (Sankh et al .…”

Biobased organic acids production by metabolically engineered microorganisms

“…Moreover, low pH fermentation to free succinic acid with direct crystallization has been shown to be the most attractive from an environmental perspective, compared with other fermentation routes and petrochemical processes [21]. In this light, recently isolated yeast Issatchenkia orientalis SD108, that is tolerant to low pH and high concentrations of organic acids, has been engineered through enhancing the reductive TCA cycle to produce succinic acid (Figure 1) [22]. Bioamber/Mitsui have switched from their engineered E. coli system to low pH yeast technology using the yeast Candida krusei, which they licensed from Cargill [15].…”

Physiological and Metabolomic Analysis of Issatchenkia orientalis MTY1 With Multiple Tolerance for Cellulosic Bioethanol Production

“…I. orientalis MF‐121 was more tolerant against high concentration of Na 2 SO 4 at pH 2.0 or at 43 °C by comparison with S. cerevisiae K‐7 . Recombinant P. kudriavzevii VTT C‐79090T produced 146 g L −1 d ‐xylonate at a low pH of 3.0 or succinic acid …”