Volume 19 Part 1 Article 2: Comparison of Diffusive Gas Exchange Capacity of Filtered Spawn Bags

Volume 19 Part 1 Article 2
Year 2016
Title: Comparison of Diffusive Gas Exchange Capacity of Filtered Spawn Bags
Author: Van Nuffel J., Moreaux K., Van de Heyning R., Verfaillie M., Vergeyle P.

In this experiment a comparison was made of 4 different spawn bags (SacO2, Bischof & Klein, Unicorn 3T and Unicorn 3B). Equal amounts of substrate were inoculated with equal amounts of Lentinula edodes spawn. Of every type 5 repetitions were executed resulting in a total of 25 bags. The gas distribution was measured daily for 15 days in all bags. Results showed that during the spawn run, the internal buildup of considerable CO2 concentrations was observed in all bags. Vitality tests showed that mycelium grown in higher CO2 concentrations showed more vigor than mycelium grown in lower CO2concentrations. Inside the bags however, these concentrations are highly dependent on the filter type and position. Most bags developed an increasing CO2 gradient with the progression of the spawn run. Filter strips, located on the headspace (Bischof & Klein), induced the highest gradients (90% gradient), followed by bags with filter patches in the headspace: Unicorn 3T (67% gradient) and Unicorn 3B (35% gradient). The bags with filter strips touching the spawn (SacO2) showed little or no CO2 gradient (5% gradient). Leap-off test results showed that kernels grown in higher CO2 concentrations were faster to gain a foothold on the petri dish than kernels which endured lower concentrations. Also, mycelium that showed suffocation symptoms showed little to no growth the first few days, but picked up speed after establishing first growth. Further testing in combination with a number of other parameters, like O2 concentrations and temperature, will be conducted.

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