I'm currently monitoring the pH values during the spawning run / mycelial growth of Pleurotus eryngii throughout the mycelial stage (4 weeks), before fruit body development begins. During this period, I’ve noticed a trend that’s confusing me.
In the first week, I observe an average increase in pH of about 3.65% (becoming more alkaline), followed by a sharp decline (becoming more acidic) by the end of the 4-week period. While I’m starting to understand the reasons behind the drop in pH later on, I’m struggling to explain the initial increase in pH during the first week.
Could anyone point me in the right direction to help me understand this initial shift?
I don't know, but you could consider two reactions that raise pH which are easy to measure:
Sorry I forgot to define my abbreviation. It is a common term in wastewater and biogas field. VFAs are volatile fatty acids. This would mainly be acetic and propionic acid. These small acids are formed by hydrolysis of natural organic matter. I assume then the substrate is wetted they are formed and the fungus will initially consume these before it start degrading the fibers.
Henrik Rasmus Andersen
Thank you for the clarification. Wastewater and biogas aren’t my areas of expertise, despite the nature of my inquiry.
To answer your assumption: yes, water is added to the substrate to reach a specific moisture content. The substrate itself is wood-based and enriched with proteins prior to inoculation. It is then left to incubate for a set period before being shipped to the client, where it will than develop the fruiting body.
I’ll need to look further into acetic and propionic acid to fully understand their role. Thank you again for the helpful information.