Production of selenium-enriched microalgae as an animal feed supplement

The primary goal of this proposal is to investigate the potential of generating an alternative source of organically bound selenium from microalgae. Selenium is commonly supplemented into animal feed, nutraceuticals, and human food due to its numerous health benefits. Selenium has been reported to prevent cardiovascular and neurological diseases, aging, infertility, thyroid function, and infections. In addition to the benefits to human health, selenium also promotes the growth and productivity of fish, birds, and mammals. Selenium deficiency has also been found to cause various diseases in animals. Despite the obvious health benefits of selenium, many of the sources of selenium such as selenium salts are not bioavailable for human and animal uptake. One source of selenium which is bioavailable is organically bound selenium. A common source of organically bound selenium is in specially fermented selenium yeast; however, this selenium yeast is costly to produce and has some health concerns itself. Due to these realities, a low-cost, sustainable, bioavailable source of selenium is in great need.To address this issue, we propose to develop, optimize, and evaluate a process to produce a microalgae biomass that is high in bioavailable organic selenium. We will use our patent pending revolving algal biofilm (RAB) cultivation system that has demonstrated 10 times higher algal productivities compared to conventional algal culture systems. Additionally, our RAB system does not require the expensive harvesting and dewatering technologies that cripple the economics of conventional algae cultivation technologies. In our preliminary study, we demonstrated that our RAB system is capable of rapid accumulation of selenium in the algal biomass at a very high level. If successful, this proposal will lead to a new bioavailable selenium source that will promote healthy people and animals.Three objectives will be pursued to achieve the goal of developing a new microalgae product high in bioavailable organically bound selenium: (1) optimize selenium accumulation in algae biomass by altering cultivation conditions, (2) evaluate the use of selenium-containing food and feed manufacturing effluent as a free nutrient and selenium source for the algal growth medium, and (3) evaluate the bioavailability of selenium contained in algae biomass.The anticipated results of this project are threefold: (1) the selenium content and profile in the algal biomass will be understood, (2) the bioavailability of selenium in algal biomass will be determined, (3) understand if a previously unutilized effluent stream high in nutrients and selenium from a food and feed manufacturing plant can be used as growth medium for algal growth. Collectively these results will give GWT the knowledge to make a go/no-go decision on the scale up of the RAB system for production of a selenium rich algal biomass.