Alma Rodriguez Estrada
"Arbuscular Mycorrhizae (AM) in Secondary Succession"
Grant in Aid of Research
Final Report: "Edible mushrooms are cultivated on a vast variety of lignocellulosic substrates including straws, seed hulls, sugarcane bagasse, etc. Testing novel substrates for mushroom cultivation commonly implies the successful conversion of plant biomass to mushrooms evaluated through total yields, biological efficiency, mushrooms size, etc. However, testing for quality of the product and safety for human consumption is rarely considered. As part of the GIAR grant received, oyster mushrooms (Pleurotus ostreatus) grown on Phragmites australis biomass and deink sludge from paper recycling with and without anaerobically digested dairy solids supplementation were tested in regards of their safety for human consumption. Dried mushrooms were evaluated for concentrations of the following minerals and heavy metals: cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), lead, (Pb), zinc (Zn), and lithium (Li). Samples were analyzed at the Wisconsin Soil and Plant Analysis Lab, University of Wisconsin - Madison. Minerals and heavy metals concentrations were compared to the reference dose for chronic oral exposure (RfD) listed by the U.S. EPA in the Integrated Risk Information System (IRIS). The RfD is an estimate of human population daily exposure likely to have unappreciable risk of deleterious effects over lifetime. There are not limits for all minerals and heavy metals listed above and some values are below detection levels through common analytical techniques. Results showed that manganese and nickel concentrations (8.6 mg/kg and 0.41 mg/kg, respectively) in mushrooms were much higher than the listed RfD values. However, the Recommended Daily Allowance (RDA) established by the Institute of Medicine for manganese is 1.9 - 2.3 mg/day and the upper limit intake is 6 - 11 mg/day (for a population of male and female adults). Therefore, a serving size of fresh mushrooms (85 g) will provide 0.73 mg/day. Upper limit intake for nickel is 79 to 105 μ/day and a serving size of mushrooms grown on the above mentioned substrate will provide 35 μg/day. Based on those results, it is concluded that manganese and nickel concentrations in mushrooms grown from a 50% / 50% Phragmites/deink sludge are within safety limits for human consumption."
"Isolation and Identification of Microorganisms from Soil Samples"
Grant in Aid of Research