E. O. Akpaja

This study examined the effects of illumination on the vitamin D and secondary metabolite contents of Pleurotus ostreatus (oyster mushroom) under different exposure durations. Fresh samples of the mushroom were subjected to varying illumination periods using both sunlight and ultraviolet (UV) light for 1, 2, 4, 6, and 8 hours. Ethanol extracts of the samples were subsequently analyzed for vitamin D and secondary metabolite contents. The results revealed that exposure to sunlight for six hours yielded the highest vitamin D content, indicating this as the optimum illumination period for vitamin D synthesis in P. ostreatus. Conversely, exposure to ultraviolet light showed inconsistent effects, with prolonged exposure leading to denaturation and a decline in vitamin D concentration. The impact of illumination on secondary metabolite constituents varied according to the observed secondary metabolite, light-sensitive compounds such as flavonoids and phenols decreased with extended exposure with flavonoids showing an optimum value display at 6 hours (0.39 mg/g) but decreased slightly to 0.36 mg/g after 8 hours, while saponins and terpenoids increased, possibly due to the softening of tissue cells that enhanced their production. Cardiac glycosides, being more resistant to light, remained relatively stable across treatments, maintaining (0.35 mg/g), with no statistically significant difference (p > 0.05). These findings highlight the significance of the effects of exposure of mushroom samples to sunlight and ultraviolet light at different time periods. The study also provides a basis for further research on optimal illumination at different time points to enhance and maximize vitamin D and phytochemical components of Pleurotus ostreatus.

The purpose of this study was to determine the effect of selected tuber-based media on the vegetative growth of the fungus Volvariella volvacea (Bull. Ex Fr.) Sing. Pure culture of V. volvacea was gotten from the African Centre for Mushroom Research and Technology Innovations, University of Benin, Benin City, Nigeria. The pure culture was expanded aseptically on potato dextrose agar and stored until utilized. This evaluation was carried out by puncturing the pure culture with already sterilized cork borer then the inoculum was collected with an already sterilized loop and inoculated at the center of the formulated culture. The culture media were subjected to different orientations. This procedure was carried out for the five replicates of each formulated medium after which they were taken to the incubation room. The growth biometry was taken after 24 hours for 6 days. Potato dextrose agar recorded the highest mycelia growth on the different plate orientations while cocoyam dextrose agar and white yam dextrose agar recorded the lowest mycelia growth on plates with an upward orientation and plates with a downward orientation respectively. From this study it has been observed that the vegetative growth of Volvariella volvacea is influenced by the plate orientation and the tuber used to prepare the culture media. This study has shown that sweet potato and water yam can be considered as viable alternatives for potato in the preparation of culture media for the fungus. Key words: Fungi, Plate orientation, Vegetative growth.

The purpose of this study was to determine the effect of selected tuber-based media on the vegetative growth of the fungus Volvariella volvacea (Bull. Ex Fr.) Sing. Pure culture of V. volvacea was gotten from the African Centre for Mushroom Research and Technology Innovations, University of Benin, Benin City, Nigeria. The pure culture was expanded aseptically on potato dextrose agar and stored until utilized. This evaluation was carried out by puncturing the pure culture with already sterilized cork borer then the inoculum was collected with an already sterilized loop and inoculated at the center of the formulated culture. The culture media were subjected to different orientations. This procedure was carried out for the five replicates of each formulated medium after which they were taken to the incubation room. The growth biometry was taken after 24 hours for 6 days. Potato dextrose agar recorded the highest mycelia growth on the different plate orientations while cocoyam dextrose agar and white yam dextrose agar recorded the lowest mycelia growth on plates with an upward orientation and plates with a downward
orientation respectively. From this study it has been observed that the vegetative growth of Volvariella volvacea is influenced by the plate orientation and the tuber used to prepare the culture media.