Inoculant production of Pisolithus sp. in submerged culture under agitation

Ectomycorrhizal fungi inoculation can increase the sustainability of planted forests hence the inoculant production should be optimized. The objective of this study was to determine the agitation speed and time of growth for maximum production of mycelium of D216 isolate of Pisolithus sp. The treatments were established by factorial 6x3, being six agitation conditions and three different times (days) of growth. The kinds of agitation used were: Without agitation, gentle manual agitation every two days and orbital agitation speed of 50, 100, 200 and 250 rpm.  The times of growth were 14, 21 and 28 days. The mycelium mass was generally single and remained on the surface of the culture medium when grown without agitation or with manual agitation. Spherical mass units formed under agitation and grew submerged. The dry mass production of mycelium of D216 isolate was higher when grown under agitation of 200 rpm, followed by 250 and 100 rpm. For all agitation system, the production of mycelium did not increase after 14 days. The maximum production of mycelium dry mass of D216 isolate of Pisolithus sp. was obtained in the agitation speed of 200 rpm for 14 days. The elevation of the agitation to 250 rpm decreased the mycelium dry mass production of Pisolithus sp. In the absence or in lower agitation speeds, the mycelium dry mass was minimal. Using the ideal speed for maximum mycelium production and adjusting other growing conditions can decrease the risk of contamination, the production time and cost of the inoculant and encourage the use of this biotechnology. Key words: Ectomycorrhizal fungi, inoculation, mycorrhiza, planted forests.