SBIR Phase I: One-step Production of Lactic Acid from Lignocellulosic Biomass by Recombinant Cellulolytic Bacillus subtilis

This Small Business Innovation Research Phase I project will develop a new ultra-low-cost platform for the production of lactic acid directly from pretreated lignocellulosic biomass in a single step by using a novel recombinant cellulolytic Bacillus subtilis strain. Lactic acid is the precursor of polylactic acid (PLA), an environmentally friendly biodegradable plastic. Currently, lactic acid is commercially produced through bacterial fermentation based on corn starch or cane sugar, which are food and animal feed. Cellulosic biomass is the most abundant natural renewable resource, which has great potential in the production of valuable biocommodities for both short- and long-term sustainability. However, the process for converting non-food lignocellulosic material into lactic acid is not feasible yet due to the high cost of cellulase involved in cellulose hydrolysis and also to the use of fastidious culture media. Through the systematic genetic engineering and metabolic engineering, this project will convert noncellulose- utilizing B. subtilis to an efficient lignocellulose utilizer and to produce lactic acid at high yield and titer, suitable for industrial fermentation. The broader impact/commercial potential of this project is that the proposed recombinant cellulolytic B. subtilis would be an ultra-low-cost platform for producing lactic acid from non-food biomass, with obvious advantages over other developing CBP microorganisms. Also, this effort would serve as a model system to convert other industrially important microorganisms into cellulose utilizers and result in use of renewable and less expensive substrates for the production of valuable products. Lactic acid was identified by the U.S. DOE as one of the top 30 value-added and potential buildingblock chemicals made from biomass. There are many potential derivatives of lactic acid, some of which are new chemical products and others represent biobased alternatives to chemicals currently produced from petroleum. The use of lactic acid for making biodegradable PLA is growing rapidly, given the rising demand for environmentally friendly packaging. The production of PLA releases fewer toxic substances than making petroleum plastic, consumes less energy, and releases an estimated two-thirds less greenhouse gas. PLA can be composted, incinerated or recycled. There is no doubt that the consumption of the biodegradable plastic products derived from lactic acid would decrease the growing environmental pollution and attract greater consumer interest towards the use of green products.