Wheat straw fermentation

Sequential culture is a type of mixed culture in which the second organism is added after growth of the first organism has ceased. This method can be used to maximize utilization of the nutrients in the substrate. For example, the protein content of wheat straw fermented by Chaetomium cellulolyticum or... 

Retained by Weight for the 40 g for the " C Labeled Lignin Membrane Wheat Straw Fermentation Fermentation... 

Recovery of cellulases from wheat-straw hydrolysis fermentation broth [83]... 

We can illustrate fermentation processes using the process developed by Iogen to convert lignocellulosic materials such as wheat straw into ethanol (Fig. 2.10) [66]. The straw is chopped and milled prior to a steam-explosion pre-treatment to... 

Fig. 2.10 I ogen s fermentation process of wheat straw into ethanol [63],...

When wheat straw was fermented in LSF, the FP cellulase level reached 6 lU/ml (300 lU/g cellulose or 120 lU/g substrate) (Table I) by day 11, decreasing thereafter. This showed that SSF was better than LSF for cellulase production when using wheat straw. 

Wheat straw. FP cellulase per unit volume in LSF was very low at 1% wheat straw. It doubled when the wheat straw concentration was raised to 5%. But the FP cellulase per unit weight of wheat straw produced at 5% concentration was reduced to almost one-half that obtained on 1%. Similar observations were made with the )3-glucosidase and xylanase activities (Table IV). The low productivity of all the enzymes could be the result of an O2 transfer problem in the thick fermentation medium in the LSF. 

Table IV. Composition of Cellulase Systems of Trlchoderma reesel QMY-1 produced on Wheat Straw and Wheat Bran Under Liquid and Solid-State Fermentation...

Table VIL Comparison of Hydrolysis of Delignified Wheat Straw with Cellulase Systems of Trichoderma reesei QMY-1 Produced Under Solid-State Fermentation ...

Recent studies have proven ethanol to be an ideal liquid fuel for transportation and renewable lignocellulosic biomass to be an attractive feedstock for ethanol fuel production by fermentation (1,2). The major fermentable sugars from hydrolysis of lignocellulosic biomass, such as rice and wheat straw, sugarcane bagasse, corn stover, corn fiber, softwood, hardwood, and grasses, are D-glucose and D-xylose except that softwood... 

Table 5 shows the achieved ethanol concentrations after 24 h of fermentation and the calculated ethanol yield as percent of theoretical. After 1 d of fermentation the ethanol concentrations varied from 12.1 to 13.8 g/L, corresponding to 78.4 and 90.3% of the theoretical yield. Glucose was totally consumed after 6 h of fermentation following pretreatment with 0.5% H2S04. The maximum ethanol concentration was also reached after 6 h in these cases, but when 2% H2S04 was used in pretreatment, glucose was consumed more slowly and the formation of ethanol needed more time. However, even in these cases the achieved ethanol yield was about 85% of the theoretical. These results are quite similar to those achieved after fermentation of wet oxidized wheat straw in a previous study (17). 

Wheat bran, which contains cellulose, protein and other nutrients, is an excellent medium for solid-state fermentation [25,47]. Wheat bran is also widely used in other fermentation industries but is still too expensive for economic cellulase production. Agricultural residue is cheaper. For example [30,48], after pretreatment by 4 % NaOH at 121 °C for 0.5 -1.0 h, wheat straw was used as raw material. After mixing with nutrient salts, adding water to a water content of 80%, then adjusting the pH to 5.8, the medium was used for solid-state fermentation. The final cellulase activity was reported to be as high as 200-430 FPIU per gram of cellulose. Deschamps et al. [49] used a mixture of wheat straw and bran (80 20) as raw materials for solid-state fermentation the... 

More than twenty years ago, it was recognized that cellulosic biomass, including agricultural residues (such as corn stover, rice and wheat straws, and sugarcane bagasse), municipal wastes (such as yard and paper wastes), and industrial wastes (such as wastes from paper mills), is an attractive feedstock for ethanol-fuel production by fermentation because cellulosic biomass is not only renewable and available domestically in most countries but also available at very low cost and in great abundance. 

Fig. 14. Fermentation of glucose and xylose present in the crude hydrolysates of wheat straw by genetically engineered Saccharomyces yeast strain 1400 (pLNH32). The hydrolysate was provided by St. Lawrence Technologies Inc., Canada. Symbols solid square glucose solid circle xylose (90%) and small amount of galactose (10%) solid triangle ethanol open triangle xylitol open square glycerol...

Figure 3 illustrates the effect of chemical processing by a method previously developed (46) on the in vitro digestibility of wheat straw. The lower curve shows the digestion level for the untreated wheat straw after a 48 hour fermentation period. The upper curve demonstrates how treatment of the wheat straw with 6% alkali has increased the DE (rep-... 

Enzymatic Hydrolysis and Ethanol Fermentation of High Dry Matter Wet-Exploded Wheat Straw at Low Enzyme Loading... 

This paper investigates the potential of xylanase production in solid-state fermentation from soya oil cake by Penicillium canescens lO-lOc using a multi-layer-packed bed reactor. Previous studies reported xylanase production by this strain in solid-state fermentation from wheat straw in flasks [1]. 

Xylose is the major sugar present in the hemicellulose fraction of agricultural residues, such as wheat straw. Because the raw material cost is greater than one-third of the overall ethanol production cost [5], fermentation of xylose together with glucose is needed to improve the economics of any lignocellulosic-based bioethanol process. 

The ethanol yields obtained in this study are considerably higher than those reported for fermentation of the undetoxified hemicellulose fraction of wheat straw by various pentoseutilizing yeasts and are comparable with the highest yield of 0.41 g per gram of sugars... 

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