Quantification of Physical and Chemical Properties, and Identification of Potentially Valuable Components from Fuel Ethanol Process Streams

Abstract

Cereal Chem. 90(1):70-79Wider exploration of ethanol coproduct uses is necessary as the ethanol industry continues to face challenges. Currently, process streams such as thin stillage and condensed distillers solubles (CDS) are processed into distillers dried grains with solubles and used as animal feeds, but other higher value opportunities may exist. The objective of this study was to identify chemical components and quantify physical properties of CDS and thin stillage. Protein, organic acid, and sugar profiles were determined. Zein protein was identified, and glycerol was determined to have a concentration of 18.8 g/L in thin stillage and 63.2 g/L in CDS. Physical properties including density, thermal conductivity, thermal diffusivity, and rheological behaviors were also examined. Thermal conductivity of thin stillage and CDS was approximately 0.54 and 0.45 W/m°C, respectively. Quantification of the physical properties and identification of the chemical constituents pave the way for exploration of new value-added uses for thin stillage and CDS.

Methods to Recover Value-Added Coproducts from Dry Grind Processing of Grains into Fuel Ethanol

“…These metabolites include glycerol, lactic acid, ethanol, acetic acid, and isopropanol, succinic acid, etc. 12,14,15 Among the components found in CDS, glycerol, a byproduct of yeast fermentation, is considered the major one responsible for the dewatering difficulty of CDS. There are two reasons for this difficulty.…”

Towards a Valorization of Corn Bioethanol Side Streams: Chemical Characterization of Post Fermentation Corn Oil and Thin Stillage

“…The dry matter was composed of fats (19-30% dry mass), true proteins (8.8-12.8% dry mass), calculated by subtracting nonprotein N to total N, ash (7.8-11.4% dry mass), and total dietary fiber (8.4-24.4% dry mass). The remaining fraction (36-53% dry mass) may be ascribed to oligosaccharides, unfermented sugars, organic acids, and glycerol left after fermentation, as indicated in the literature [23]. Minor variations observed in the thin stillage composition can be caused by seasonal differences in maize composition and also by slight changes in process parameters such as acid addition rates, enzyme loadings, temperatures, and fermentation conditions.…”

“…pH is within the range of internal limits of pH 3.7-4.7. The acidic pH is mainly attributable to the presence of organic acids, mainly acetic, lactic, and propionic acids resulting from the fermentation process [18,23]. The dry matter value in the series of samples analyzed was almost stable (6.8-9.9%), indicating constant conditions of the biotech process.…”

“…Literature studies by other authors have highlighted the organic and inorganic compounds present in grain-based ethanol thin stillage and post fermentation corn oil [12,[18][19][20][21][22][23] but, to our best knowledge, no manuscript reports on a systematic study for an extensive period of time focused on chemical characteristics of co-products of a commercial dry-grind corn-based bioethanol facility.…”

Gaseificação de vinhaça em água supercrítica.

“…A vazão do sistema como um todo foi determinada com base na produção de vinhaça em uma safra de 167 dias, conforme Wood et al (2013) O método base selecionado para o modelo foi o de Soave-Redlich-Kwong (RK-SOAVE). Este modelo é geralmente utilizado para substâncias pouco polares, mas é particularmente indicado para altas temperaturas e pressões, como aplicações em estado supercrítico (TISDALE, 2004).…”