Monday, April 29, 2013
Exhibit Hall
Increasing energy demands with limited resources have created a need for sustainable and renewable energy sources derived from low value substrates. Algae used for the production of biodiesel generate algal carcass as waste material. Our analysis of such material reveals it contains over 5% carbohydrate, with glucose as the most abundant monosaccharide. Lactobacillus casei ferments hexose sugars to lactic acid, which has many different valuable applications through a wide range of industries. This project is exploring use of L. casei to ferment algal carcass material into a valuable co-product, lactic acid. Growth experiments of L. casei ATCC 334 where conducted using algal carcass solutions, algal carcass solutions supplemented with growth nutrients, or the laboratory medium APT. The supernatant was collected and assayed for lactic acid concentrations. L. casei ATCC 334 demonstrated the ability to grow with algal carcass solely as the nutritive source. At low algal carcass concentrations, growth was not as extensive as with APT, and glucose supplementation to an equivalent concentration showed this was the limiting nutrient. However, the percentage of available carbohydrate converted to lactic acid in algal carcasses versus APT containing equivalent carbohydrate levels was 27.4% and 70.8%, respectively, suggesting L. casei may produce other end products from this substrate. Metabolomics analysis will be initiated to obtain a more comprehensive understanding of L. casei metabolism on this unique substrate. Overall, the ability of L. casei to ferment algal carcasses demonstrates the potential for creating valuable co-products from this low value biofuels-related waste material.