Final Report: Use of Selenium-Contaminated Plant Waste Materials from Phytoremediation in Central California for Production of Selenium-Enriched Edible MushroomsEPA Grant Number: SU836036
Title: Use of Selenium-Contaminated Plant Waste Materials from Phytoremediation in Central California for Production of Selenium-Enriched Edible Mushrooms
Investigators: Lin, Zhi-Qing , Morrissy, Jennifer , Hong, Jie , Haddad, Samuel
Institution: Southern Illinois University - Edwardsville
EPA Project Officer: Hahn, Intaek
Project Period: August 15, 2011 through August 14, 2012
Project Amount: $14,539
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2011) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Agriculture , P3 Challenge Area - Built Environment , Pollution Prevention/Sustainable Development , P3 Awards , Sustainability
This study evaluated the feasibility of using selenium-polluted plant waste materials harvested from phytoremediation filed sites in the San Joaquin Valley, central California to produce selenium-enriched edible mushrooms. As a novel research concept that integrates phytoremediation and biofortification processes, we have developed an environmentally sound and sustainable management strategy for selenium phytoremediation in central California and for the production of selenium-enriched edible mushrooms. This study promotes the on-farm phytoremediation treatment systems to reduce and remediate selenium-contaminated agricultural drainage wastewater in the San Joaquin Valley. By recycling selenium polluted plant waste materials instead of landfill disposal, we have successfully used Se-polluted plant waste materials harvested from phytoremediation sites to formulate selenium-laden growth substrates, a valuable asset for the production of selenium-enriched edible mushrooms.
The objectives of this Phase I study were to (1) measure Se concentrations in different edible mushroom species or varieties that are commercially produced in the US, (2) determine the ability of mushrooms to accumulate Se from the growth substrates treated with different levels of selenate or different chemical forms of Se (including selenate, selenite and selenomethione), and (3) produce Se-enriched edible mushrooms in the growth substrates containing different types of Se-laden plant materials that were harvested from the phytoremediation field sites in the San Joaquin Valley, central California.
Concentrations of Se in mushrooms of 10 different kinds that are most commonly produced in the US were investigated. The selected mushrooms included White Button mushroom (Agaricus bisporus), Portabella (Agaricus bisporus), Baby Bella (Agaricus bisporus), Shiitake (Lentinus edodes), Oyster mushroom (Pleurotus ostreatus), White Beech (Hypsizygus tessulatus), Brown Beech (Hypsizygus tessulatus), Enoki (Flanmmulina velutipes), Maitake (Grifola frondosa), and King Trumpet (Pleurotus erungli). Most of the mushroom samples contained relatively low Se concentrations of <0.25 mg kg-1 (DW), except for the three varieties of Agaricus bisporus that concentrated more Se than other mushroom species and varieties (P<0.05). The highest Se concentration of 2.68 mg kg-1 was observed in Baby Bella mushrooms. Concentrations of Se in commercially produced mushrooms varied significantly not only among different species, but also among different growers who have used different sources of growth substrate materials in mushroom production. Thus, there is a strong need to develop and produce selenium-biofortified edible mushrooms for the US market.
Concentrations of Se in growth substrates significantly affected Se accumulation in mushroom fruit bodies. When the Se concentrations in the substrates were 2, 4, and 8 mg kg-1, concentrations of Se in Oyster mushrooms were 20.6, 45.1, and 65.1 mg kg-1, respectively. The accumulation of Se in mushrooms increased significantly with increasing the substrate Se concentration.
When the growth substrate was treated with different chemical forms of Se, including selenate (SeO4), selenite (SeO3) and selenomethionine (SeMet), the highest Se concentration (31 mg kg-1) in Oyster mushroom was observed with the growth substrate that was treated with selenate, followed by the SeMet treatment (26 mg Se kg-1) and the selenite treatment (23 mg Se kg-1).
The accumulation of Se in White Button and Baby Bella mushrooms (varieties of Agaricus bisporus) was enhanced significantly by spiking the growth substrates with Stanleya pinnata leaf powders containing approximately 3000 mg Se kg-1, showing a concentration increase from approximate 1.5 mg kg-1 in the control to 30 mg kg-1 in the growth substrates treated with 5 mg kg-1 selenium from plant powders.
Because White Button and Baby Bella mushrooms are the secondary decomposers, these mushrooms need to be grown in the substrates that have been partially decomposed previously by other microorganisms. Therefore, selenium-laden plant materials need to be composted prior to being used as the growth substrate materials for White Button and Baby Bella mushrooms. In this study shoots of Elephant grass (Pennistum purpureum) and Rye grass (Leymus triticoides) were well mixed and composed along with horse manure and cottonseed meal. Using the plant compost as the growth substrate containing 0.8 mg Se kg-1, concentrations of selenium in White Button and Baby Bella mushrooms were 3.2 mg kg-1 and 3.3 mg kg-1, respectively, which is about 2-fold higher than the mushroom selenium concentrations using the Monterey growth substrates.
Selenium-laden Eucalyptus wood and rye grass tissues were used directly as the growth substrate materials to produce Se-enriched Oyster mushrooms (a primary decomposer). The Se-biofortified Oyster mushrooms accumulated 2.9 mg Se kg-1 in fruit body from the Se-contaminated plant materials containing 1.98 mg Se kg-1, compared with 0.2 mg Se kg-1 in commercially produced Oyster mushrooms. The Se biofortification treatment resulted in a 13-times increase of Se accumulation in Oyster mushrooms.
This Phase I study has successfully tested a novel concept of using selenium-laden plant waste materials harvested from phytoremediation field sites in central California as growth substrates to produce Se-enriched edible mushrooms. The accumulation of selenium in mushrooms can be substantially enhanced by increasing selenium contents and controlling the dominant chemical forms of Se in the growth substrates. The research findings of this study demonstrated the feasibility of developing a new environmentally sound and sustainable biotechnology that integrates both phytoremediation and biofortification processes for the production of seleniumbiofortified edible mushrooms.