Table 1 Overview of enzymatic assays used to screen for alcohol in biological samples.
From: Development of a high-throughput assay for rapid screening of butanologenic strains
References | Description of assay | |
|---|---|---|
1. | Commercial alcohol assay kits (e.g., Emit II Plus ethyl alcohol assay kit from Beckman Coulter) | These assays are based on the conversion of NAD+ to NADH, which accompanies the oxidation of ethanol to acetaldehyde by S. cerevisiae ADH. The increase in absorbance at 340 nm is proportional to the concentration of alcohol in the sample. The assay measures total alcohol in samples. |
2. | Scheel and Lütke-Eversloh1 | This assay uses S. cerevisiae ADH and NBT-based quantitation of alcohol. Assay was successfully adapted to measure total alcohol in ABE fermentation, but cannot preferentially detect butanol (Fig. 1). |
3. | Azevedo et al.19 | Most alcohol oxidase (AOX)-based ethanol sensors monitor O2 consumption or H2O2 formation using amperometric electrodes (− 600 mV for O2 or + 600 mV for H2O2). |
4. | Mangos and Haas20 | A colorimetric assay employed to detect methanol using AOX, peroxidase, and 2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS). |
5. | Verduyn et al.21 | An assay based on a modified AOX from Hansenula polymorpha, which lack 90% its catalase activity, an essential attribute for colorimetric alcohol assays that are centered on peroxidase-mediated oxidation of dyes. Assay is particularly suitable for determination of ethanol in fermentation broths. |
6. | This study | Employs a recombinant ADH from T. hypogea. This assay is capable of preferential quantitation of butanol in mixed alcohol substrate, including ABE fermentation broths. |
