1. I got red brown colony but not red brown clear zone. Can we say that it is a positive result
2. Tannic positive results can not be a positive on Guaiacol. Why?
3. Can I autoclave guaiacol and Tannic Acid
1. The formation of a red-brown colony indicates that the bacterium may be producing laccase. However, the absence of a clear zone around the colony suggests that the laccase activity may not be strong enough to oxidize guaiacol and form a clear zone. Therefore, it may not be considered a positive result for the guaiacol assay.
2. Tannic acid and guaiacol are different substrates for laccase. Tannic acid is a polyphenol compound that can be oxidized by laccase to form a brown precipitate. Guaiacol, on the other hand, is a simpler substrate that is oxidized by laccase to form a reddish-brown color in the presence of hydrogen peroxide. The chemical reactions involved in these assays are different, so a positive result for one substrate does not necessarily indicate a positive result for the other.
3. Both guaiacol and tannic acid can be autoclaved. However, it is important to ensure that they are properly prepared and stored to avoid contamination and degradation. Guaiacol is light-sensitive and can become oxidized and discolored over time, so it should be stored in a dark container at room temperature. Tannic acid is hygroscopic and can absorb moisture from the air, so it should be stored in a dry location in an airtight container. Before autoclaving, it is recommended to filter sterilize the guaiacol and tannic acid solutions to remove any particulate matter or microbial contamination that may interfere with the assay.
Lamia Fatima can you provide me the link to any article for the second point.
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