A Statistical Optimization Study on Dilute Sulfuric Acid Pretreatment of Distillers Dried Grains with Solubles (DDGS) As a Potential Feedstock for Fermentation Applications

2019-11-01
Distillers dried grains with solubles (DDGS) are co-product of dry-grind ethanol plant, which can be used as a feedstock for fermentation, e.g. for biofuels or other value-added products. However, DDGS loading is a critical factor in the pretreatment, hydrolysis, and fermentation, where the low DDGS loading lowers sugar concentration in the hydrolysate and yields low product concentrations, which can result in high energy cost at the recovery step, while too high loading may have inhibitory effects on the microbial growth during fermentation. Therefore, an optimal DDGS loading needs to be determined at the pretreatment step for high sugar yields. In this study, dilute sulfuric acid pretreatment of DDGS was optimized to obtain the high release of sugars with the use of high DDGS loading at an appropriate acid concentration. An experimental design was constructed with the Box-Behnken response surface method using the ranges of 5-20% (wt) DDGS, 1-5% (wt) H2SO4, and 20-60 min pretreatment times at a constant temperature of 120 degrees C. The results revealed the highest yields of sugars (0.39 g/g) at 20% DDGS, 5% (wt) H2SO4, and 120 degrees C after 1 h. The results justify complete hydrolysis of hemicellulose and residual starch fractions and provide sufficient amount of sugars for the fermentation process.
WASTE AND BIOMASS VALORIZATION

Suggestions

Comparison of common carbon sources with unhydrolyzed, dilute acid and steam hydrolyzed distillers’ dried grains with solubles for lignocellulolytic enzyme productions by fungal strains
Iram, Attia; Çekmecelioğlu, Deniz; Demirci, Ali (2023-05-15)
Distillers’ dried grains with solubles (DDGS) are the byproduct of first-generation bioethanol production. DDGS has a high fiber content, which can be used for hydrolytic enzyme production after pretreatment by physical or chemical methods such as dilute acid or semi-continuous steam explosion. This study compares the treated DDGS samples to common carbon sources such as glucose, Avicel (crystalline cellulose), and untreated DDGS along with other cellulosic materials during the production of cellulases and ...
Optimization of the fermentation parameters to maximize the production of cellulases and xylanases using DDGS as the main feedstock in stirred tank bioreactors
Iram, Attia; Çekmecelioğlu, Deniz; Demirci, Ali (2022-01-01)
Lignocellulolytic enzymes such as cellulases and xylanases are needed on the industrial scales for low cost production of biofuels and the other value-added products from lignocellulosic biomass such as distillers' dried grains with solubles (DDGS). Optimization of fermentation variables such as agitation, aeration, and inoculum size for fungal enzyme production by submerged fermentation can enhance the enzyme production levels. Therefore, this research focuses on the statistical optimization of fungal inoc...
Screening of the putative hexokinase genes from rhizopus oryzae
Alagöz, Eda; Hamamcı, Haluk; Yücel, Ayşe Meral; Department of Biotechnology (2013)
Rhizopus oryzae is a filamentous fungus which can ferment sugar to ethanol, and lactic acid. Increasing demand of the world for use of renewable carbon sources has put this and similar organisms into a position where the biotechnology industries are more and more interested with these organisms. R. oryzae can grow on some renewable carbon sources which makes it a good candidate for production of ethanol as well as lactic acid. The major use of lactic acid is in food industry and food- related application, w...
Investigation of sugar metabolism in rhizopus oryzae
Büyükkileci, Ali Oğuz; Hamamcı, Haluk; Department of Biotechnology (2007)
Rhizopus oryzae is a filamentous fungus, which can produce high amounts of L(+)-lactic acid and produces ethanol as the main by-product. In an effort to understand the pyruvate branch point of this organism, fermentations under different inoculum and glucose concentrations were carried out. At low inoculum size (1x103 spores ml-1), high amount of lactate (78 g l-1) was produced, whereas high ethanol concentration (37 g l-1) was obtained at high inoculum sizes (1x106 spores ml-1). Decreasing working volume i...
Cloning and screening of the putative hexokinase genes from Rhizopus oryzae and their heterologous expression in Saccharomyces cerevisiae
Alagoz, Eda; Acar, Seyda; Yucel, Meral; Hamamcı, Haluk (2022-06-01)
Background A filamentous fungus, Rhizopus oryzae (R. oryzae) is one of the ideal candidates for ethanol and lactic acid production due to its ability to grow on renewable carbon sources.
Citation Formats
D. Çekmecelioğlu, “A Statistical Optimization Study on Dilute Sulfuric Acid Pretreatment of Distillers Dried Grains with Solubles (DDGS) As a Potential Feedstock for Fermentation Applications,” WASTE AND BIOMASS VALORIZATION, pp. 3243–3249, 2019, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35876.