Impact of Microalgae/Cyanobacteria Co-culture on Sugar Mill Effluents

Jacob Foy, Civil and Environmental Engineering Department Louisiana State University, Baton Rouge, LA 70808: jfoy3@tigers.lsu.edu, Teresa Gutierrez-Wing, Civil and Environmental Engineering Department Louisiana State University, Baton Rouge, LA 70808: mgutie5@lsu.edu 

The search for alternative sustainable fuel sources has led to microalgae, an eco-friendly candidate that has low impact on food and water supply. Although massive potential for biofuel production lies in these organisms, an economically feasible production plan has not yet been established. For microalgae to compete with fossil fuels, creative use and re-use of resources must be explored.

Installations similar to Louisiana sugar mills have been proposed as potential biorefineries for sugar cane, energy cane, and sweet sorghum. The existing infrastructure and valuable waste products of the milling process pose an attractive location for the co-production of raw sugar, biofuels, and chemicals. Though energy cane and sweet sorghum do possess significant potential as feedstocks for bioethanol, microalgae grown using the nutrient-rich wastewater from the cane process may be a complementary option in producing biodiesel. Further, microalgae contain a number of high-value by-products, specifically pigments, which can be sold directly.

The objective of this work is to determine the impact of a native Louisiana co-culture of microalgae and cyanobacteria (Chlorella vulgaris/Leptolyngbya sp.) on wash water and evaporator effluents from a Louisiana sugar mill. The effect of the effluents on biomass productivity, nutrient uptake, and organic consumption will be quantified in an effort to determine suitability of the effluents for biomass production.