(489d) Low Cost Low Energy Deconstruction of Industrial Hemp to Make Biofuel and Bioproducts

Hemp now has the potential to become a new important bioenergy crop. The 2018 Farm Bill removed hemp, defined as the Cannabis sativa L. plant with a delta-9 tetrahydrocannabinol (THC) concentration of not more than 0.3 percent by dry weight, from the list of Schedule I controlled substances and, therefore, made hemp an ordinary agricultural commodity. Hemp is now a covered commodity under crop insurance. These actions will result in the continued increase in planted hemp acreage, already up 534% in 2019 as compared to 2018. The products from industrial hemp are numerous, and while hemp may be grown for fiber, seed/grain and seed oil, and cannabidiol (CBD; a medicinal compound without psychoactive effects of THC). Fiber, seed (and seed oil), as well as dual-cropping fiber and seed, may be accomplished in a high density, low input cropping system, in rotation with corn and soybeans and using production equipment already available to many producers and could potentially increase the profitability of corn-soybean growers in the region. Fiber, seed, or CBD only accounts a small portion of hemp plant. The rest of the plant, called hemp biomass, is treated as a waste stream now. This project aims to convert this biomass waste into useful chemicals, such as ethanol through hydrolysis and fermentation.

Hemp biomass lies in the category of lignocellulose. Before used as the feedstock for fermentation, the cellulose and hemicellulose in lignocellulosic biomass needs to be converted into sugars first. This conversion typically contains two steps: pretreatment and enzymatic hydrolysis. The high cost on this conversion prevents its scaling-up and wide application. This project aims to reduce the cost on the conversion of hemp biomass to sugars. We developed a low cost pre-pretreatment incorporating with storage followed by low cost pretreatment while still maintaining a high sugar yield. Then the hemp hydrolysates will be evaluated as carbon sources for fermentation to make three products: bioethanol from an engineered S. cerevisiae which can consume xylose; platform chemical, isoprenol, from an engineered E. coli strain; bioplastic, polyhydroxyalkanoates (PHA), from Pseudomonas putida.