Lignocellulosic hydrolysates production

Ethanol production depends not only on the sugar yield, but also on the fermentability of the solution. To investigate the fermentability of the pretreated com stover, fermentations were performed with baker s yeast. Baker s yeast has often been proposed as the best organism for the fermentation of lignocellulosic hydrolysates (28,29) and has the advantages that it is quite robust and was found to be less sensitive to inhibitors than cultivated yeast (30,31). 

Fig. 8 a, b. a PCA classification of lignocellulose hydrolysates from pine, spruce, aspen and birch using a combination of MOS, MOSFET and CP sensors, b Prediction of the ferment-ability of the same hydrolysates expressed as specific ethanol production rate using ANNs with topologies adapted to the sensor array (from [34] with permission of ACS)... 

The unfavorable energy balance notwithstanding, the fermentation of ethanol, as well as other chemicals, from lignocellulose hydrolysate is considered highly desirable by some to avoid competition with food production. We note, however, that the large scale processing of waste lignocellulose runs counter to sensible... 

Abiksson B, Rose SH, van Zyl WH, Sjode A, Nilvebrant NO, Jonsson LJ. (2009). Cellulase production from spent lignocellulose hydrolysates by recomhimnt Aspergillus niger. Appl Environ Microbiol, 75(8), 2366-2374. 

Fujitomi K, Sanda T, Hasunuma T, Kondo A. (2012). Deletion of the PH013 gene in Sac-charomyces cerevisiae improves ethanol production from lignocellulosic hydrolysate in the presence of acetic and formic acids, and furfural. Bioresour Technol, 111, 161-166. 

Starch containing materials can also be used for the fumaric acid production, because R. arrhizus NRRL 2582 contains amylase that readily hydrolyzes starch (Rhodes et al. 1962). Moresi et al. 1991 used potato flour as feedstock for R. arrhizus and although fumaric acid was the main metabolic product, a volumetric productivity of only 0.35 gL" h" was achieved. Recently, lignocellulose hydrolysate was used with R. arrhizus DSM 5772 (Xu et al. 2010 Julio et al. 2011).ln all cases the performance of the fermentation was lower than with glucose, but might still be economically attractive because feedstock costs are important. 

Parawira, W. and Tekere, M. (2011) Biotechnological strategies to overcome inhibitors in lignocellulose hydrolysates for ethanol production review. CrU. Rev. Biotechnol, 31 (1), 20-31. 

In addition to cellulose, cellobionic acid is another carbon feedstock that is commonly found in lignocellulose hydrolysate. Desai et al. [97] demonstrated that cellobionic acid could be used as a sole carbon source for the growth and production of isobutanol in E. coli. They were able to produce 2.7 gl of isobutanol from 10.4 gl of commercial cellobionic acid [97]. 

Zhao (2005) described the possibility of SCO production from lignocellulose hydrolysates, the biomass-to-biodiesel three-step plan lignocellulose biomass depolymerization into fermentable sugars, their conversion into microbial lipids by oleaginous microorganisms, and the chemical transformation of their lipids into biodiesel. 

To date, SCO production from lignocellulosic biomass was usually carried out through a batch fermentation mode. It is possible that using a fed-batch or crmtin-uous fermentation mode could fulfill the high-cell-density cultivation on lignocellulosic hydrolysates, and this is undoubtedly beneficial for the industrialization of SCO production (Huang et al. 2013). Anschau et al. (2014) indicated the possibility... 

In summary, these works showed the great potential of SCO production from lignocellulosic biomass. The use of lignocellulosic hydrolysates as substrates could serve as the basis for the industrialization of SCO production. However, many problems in this process stiU exist that must be solved. 

Biological Production of Polyhydroxyalkanoates frran Lignocellulosic Hydrolysates 85... 

Biological Production of Polyhydroxyalkanoates from Lignocellulosic Hydrolysates... 

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