A continuous, farm‐scale, solid‐phase fermentation process for fuel ethanol and protein feed production from fodder beets

Abstract

Fuel ethanol (95%) was produced from fodder beets in two farm-scale processes. In the first process, involving conventional submerged fermentation of the fodder beets in a mash, ethanol and a feed (PF) rich in protein, fat, and fiber were produced. Ethanol yields of 70 Llmetric ton (17 gallton) were obtained; however, resulting beers had low ethanol concentrations [3-5% (vlv)]. The high viscosity of medium and low sugar, beet mashes caused mixing problems which prevented any further increase of beet sugar in the mash. This severely limited the maximum attainable ethanol concentration during fermentation, thereby making the beer costly to distill into fuel ethanol and the process energy inefficient. In order to achieve distillably worthwhile ethanol concentrations of 8-1O% (vlv), we developed and tested a solidphase fermentation process (continuous). In preliminary trials, this system produced fermented pulp with over 8% (vlv) ethanol corresponding to an ethanol yield of 87 Llmetric ton (21 gallton). Production costs with this novel process are $0.47/L ($1.77/gal) and the energy balance is 2.1 l . These preliminary cost estimates indicate that fodder beets are potentially competitive with corn as an ethanol feedstock. Additional research, however, is warranted to more precisely refine individual costs, energy balances and the actual value of the PF.

Saccharification of Beet Pulp and Its Reduced Derivatives

“…13,14) The primary reason that sugar beets are not currently being used on a wider scale for ethanol production is the lack of a practical process for fermentation. 15) In addition, it is important to develop the process of beet pulp saccharification for the carbon source of yeast ethanol fermentation, because the total sugar of beet pulp amounts to 4-5%, i.e., complete use of beet pulp sugar would lead to actually 1.3-fold increase in the amount of usable sugars in beet materials.…”

Optimization of Protein Production By Candida Utilis In Industrial Vinasse With Applicability In Food

“…The groups were confirmed by cluster analysis (Figure 6), which exhibits distinct colors to form groups by similarity using the Mahalanobis distance for the first two principal components with autoscaling of data and using PCA for data reduction. The duration of 32 hours was identified as optimum for yeast growth even though the concentration of the inoculum suffered variations (Gibbons et al, 1984;Manilal et al, 1991). When the growth curves of each of the 16 significant treatments per unit time were considered, the interval of 32 hours was found to be the most appropriate (Figure 9).…”

Integrated biorefineries with engineered microbes and high-value co-products for profitable biofuels production

“…Moreover, it is not practical to simply grind these feedstocks and blend them in water to conduct submerged fermentation. So much water would be necessary to achieve a flowable solution that final ethanol titers would be unacceptably low (Gibbons et al 1984(Gibbons et al , 1986. The alternative of extracting sugars or pressing out juice would remove non-fermentable solids and permit use of traditional fermentors.…”

“…Both these routes would require ultrahigh-throughput screening, as the factorial combinations of genes involved in this approach is enormous. s For concept plant form using shared utilities and operational staff (Gibbons et al 1984(Gibbons et al , 1986.…”