Yeast S. cerevisiae engineering technique and carbon source | Isobutanol concentration and/or yield | Observations | Reference |
---|---|---|---|
Overexpression of biosynthetic genes ILV2, ILV3, and ILV5 in valine metabolism. Aerobic batch cultures in 40Â g/L glucose. | 4.12Â mg/g glucose | First report of isobutanol production by yeast. (2011) | [37] |
Expression of a cytosolic pathway consisting of ILV2, ILV5, ILV3, ARO10, and ADH2, and deletion of the first gene of the mitochondrial pathway. Batch cultures in 4% glucose. | 630Â mg/L, | The highest titer reported up to the date (2012) | [36] |
15Â mg/g glucose | |||
Characterization of an alternative metabolic pathway for butanol and isobutanol production, using glycine as a substrate via glyoxylate and α -ketoacids intermediates. | 58 mg/L | Isobutanol from glycine (2013) | [38] |
Elimination of competing pathways in strains lacking genes encoding members of the pyruvate dehydrogenase complex (LPD1) and resolving the cofactor imbalance by overexpression of enzymes responsible for transhydrogenase-like shunts transforming NADH into NADPH. 24Â hours batch fermentation in 100Â g/L glucose. | 1620Â mg/L, | The highest titer reported hitherto (2013) | [39] |
16Â mg/g glucose | |||
Compartmentalization of the Ehrlich pathway into mitochondria. | 635Â mg/L | Increased isobutanol production by 260% (2013) | [40] |
Batch semi-aerobic cultures in 20% glucose. | |||
Fermentation of D-xylose directly to isobutanol: Overexpression of an optimized, cytosolically localized valine biosynthesis pathway together with xylose isomerase XylA from Clostridium phytofermentans, transaldolase Tal1 and xylulokinase Xks1, ketoacid decarboxylase Aro10 and alcohol dehydrogenase Adh2. | 1.36Â mg/L | Isobutanol from xylose (2013) | [41] |
0.16Â mg/g D-xylose. | |||
Genes involved in isobutanol production (ILV2, ILV3, ILV5, ARO10, and ADH2) overexpressed in an ald6Δbat1Δ strain (to eliminate competing pathways) expressing LEU3Δ601 (to activate transcription of endogenous genes in the valine and leucine biosynthetic pathways) | 376.9 mg /L | Transcriptional activation (2014) | [42] |
Closed tube cultures with 100Â g/L of glucose as substrate |