Assistant Professor South Dakota State University Brookings, South Dakota, United States
Introduction: The sunflower is one of the most important oilseed crops grown in the world for its use as edible and biodiesel oil. The preprocessing of sunflower seeds prior to the oil extraction results in the production of screens, a by-product. The sunflower screens include parts of seeds, hulls, and all other waste generated from the processing of sunflowers. This combination of materials has a higher oil and protein content than the sunflower hulls alone. The screens are currently used as animal feed (for additional roughage and oil content), bird seed, and artificial fireplace logs. However, these uses only account for a small part of the sunflower screen waste produced and demonstrates a need to find other ways to use sunflower screens. The objective of this study is to evaluate different microbial fermentation techniques, including submerged state and solid state, to determine if fermentation improves the composition of sunflower screens for its advanced use. In this study, Aureobasidium pullulans, Trichoderma reesei, and a co-cultures of A. pullulans and T. reesei were used for both fermentation techniques. Submerged fermentation was carried out at 30 °C at 120 rpm for 5 days, with samples being collected and evaluated every 24 hours. Solid state fermentation was performed statically at 30 °C for 7 days, at which point the sample was collected and evaluated. Crude protein content, total phenolic content, crude, and neutral detergent fiber were performed to evaluate the composition and any changes to the screenings due to the fermentation procedures. Preliminary results of the study indicated that fermentation is promising tool for reuse and reduction of sunflower biowaste generation, and thereby contribute to a circular economy and create more income for farmers. Future Study: A study is currently underway to assess the viability of co-culturing the filamentous fungi with mushroom yielding fungi.