Preliminary Evaluation of lutein and zeaxanthin variability in DDGS from corn ethanol facilities

Navigating the unpredictable nature of feedstock is crucial in bioprocessing. Manufacturing designs for homogeneous inputs to produce high-quality outputs, but biomass is inherently inconsistent. In bioethanol production, ethanol yield can depend on the type of corn itself in addition to the processing conditions to which it is subjected. While bioethanol processing adheres to standard operating conditions, there remains variability between facilities, an important point when considering the bioethanol byproduct DDGS as a commercial source for lutein and zeaxanthin extraction. Lutein and zeaxanthin are derived commercially from marigold flowers, which is chemically intensive and prohibits new players from entering the market. Exploring the potential of DDGS as a source of lutein and zeaxanthin would incentivize both corn growers and biorefineries but requires characterizing the differences in the yield potential of DDGS from separate bioethanol facilities. In this study, defatted DDGS from five Midwestern bioethanol facilities were examined using Soxhlet extraction with ethanol and subsequent HPLC analysis for lutein and zeaxanthin content. Using nonparametric methods and α = 0.05, it was determined that although facility appeared to have a significant effect on zeaxanthin yield, lutein yield displayed a greater degree of variability and differences in zeaxanthin yield could not be statistically ascribed to facility. Ultimately, the variability in corn growth and harvest and the downstream processing are too great to fully attribute any differences to facility alone. Future studies should consider sampling intermediate products throughout the biorefining process, as well as analyzing the incoming corn directly and comparing it to the final defatted DDGS to more fully understand how lutein and zeaxanthin partition and/or degrade during processing for a single variety of corn.