THE EFFECTS OF EDIBLE OIL SUPPLEMENTS (OLIVE OIL, VEGETABLE OIL AND PALM OIL) ON THE VEGETATIVE GROWTH OF Volvariella volvacea AND Marasmiellus inoderma.

ABSTRACT

This research was conducted to investigate the effects of edible oil supplements (olive oil, vegetable oil and palm oil) on the vegetative growth of Volvariella volvacea and Marasmiellus inoderma. The media was supplemented with edible oil at concentration levels of 4 ml, 8 ml and 12 ml per 200 ml of media. The supplemented media was inoculated with 5 mm agar block of pure cultures of V. volvacea and M. inoderma in a laminar flow chamber. After 4 days of inoculation, the highest mycelia extension was recorded for palm oil supplemented media at 8 ml/200 ml (85.0±0.00 mm) for V. volvacea. The same was recorded for M. inoderma for palm oil at 8 ml/200 ml. The least mycelia extension was observed at 12 ml/200 ml for olive oil supplemented media (63.7±3.33 mm) for M. inoderma. However, all the levels of supplementation of the oil tested, supported the growth of the mushrooms. The growth rate was fastest in media supplemented with palm oil at 4 ml/200 ml for M. inoderma (24.4±0.69 mm/day) while it was highest in palm oil at 8 ml/200 ml for V. volvacea (21.3±0.00 mm/day). The highest biomass was recorded in 12 ml/200 ml of palm oil for V. volvacea (1.112±0.26 g) and the least (0.375±0.05 g) was observed in 4 ml/200 ml of vegetable oil for the same mushroom. M. inoderma gave the highest biomass (1.186±0.21 g) in vegetable oil at 8 ml/200 ml while the least was recorded in olive oil (0.641±0.31) at 4 ml/200 ml. The cultural characteristics of the supplemented media varied in terms of density and morphology. The densities ranged from thin to very dense depending on the oil and treatment concentration. The morphologies were either fluffy, cottony or appressed. The pH of the media after complete growth in the liquid media ranged from slightly acidic to been neutral. The findings from this work have shown that edible oils can be used to enhance or increase the growth of V. volvacea and M. inoderma. The use of these oils at concentrations as high as 6 ml/200 ml of media can increase biomass production and consequently, fruit bodies production of these mushrooms.  Further study should be carried out to ascertain the level of supplementation with edible oils that will be detrimental to the growth of these edible mushrooms.