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BACKGROUND: Ultrasound‐assisted fractionation of DDGS under mild conditions was proposed for extracting xylan from dried distillers' grains with solubles (DDGS) and recovering protein‐rich DDGS residue as animal feed. The composition and properties of xylan fractions and the DDGS residue obtained by ultrasound‐assisted extraction and those by a conventional method of alkaline extraction without ultrasound‐assistance were compared. RESULTS: Compared with the result for the conventional method, a similar xylan yield of 73.8% in the extracted liquid, but higher protein content of 26.2% in the DDGS residue were obtained by the ultrasound‐assisted process with NaOH at ultrasound power of 900W and 30 °C for 20 min. The ultrasound‐assisted process has a significant impact on the sugar composition and polysaccharide side chain and polymerization degree of the xylan fractions. The DDGS residue produced by the ultrasound‐assisted process had a fine porous structure as well as greater protein and essential amino acid content. The enzymatic hydrolysis of cellulose in DDGS residue reached 70% in the initial 3 h. CONCLUSION: Ultrasound‐assisted fractionation was an efficient process for comprehensive utilization of xylan and protein in the DDGS. The xylan fractions with lower polymerization degree were perfect feedstock for xylooligosaccharide production by enzymatic hydrolysis. The DDGS residue with adequate nutrition composition and efficient digestibility had potential advantages as an alternative animal feed to DDGS. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

ABSTRACT Corncob residue as the lignocellulosic biomass accumulated phenolic compounds generated from xylitol production industry. For utilization of this biomass, Zymomonas mobilis ZM4 was tested as the ethanol fermenting strain and presented a better performance of cell growth (2.8 × 108 CFU/mL) and ethanol fermentability (54.42 g/L) in the simultaneous saccharification and fermentation (SSF) than the typical robust strain Saccharomyces cerevisiae DQ1 (cell growth of 2.9 × 107 CFU/mL, ethanol titer of 48.6 g/L). The physiological response of Z. mobilis ZM4 to the twelve typical phenolic compounds derived from lignocellulose was assayed and compared with that of S. cerevisiae DQ1. Z. mobilis ZM4 showed nearly the same tolerance to the phenolic aldehydes with S. cerevisiae DQ1, but the stronger tolerance to the phenolic acids existing in corncob residue (2-furoic acid, p-hydroxybenzoic acid, p-coumaric acid, vanillic acid, ferulic acid, and syringic acid). The tolerance mechanism of Z. mobilis was investigated in terms of inhibitor degradation, cell morphology and membrane permeability under the stress of phenolics using GC-MS, scanning and transmission electron microscopies (SEM and TEM), as well as fluorescent probes. The results reveal that Z. mobilis ZM4 has the capability for in situ detoxification of phenolic aldehydes, and the lipopolysaccharide aggregation on the cell outer membrane of Z. mobilis ZM4 provided the permeable barrier to the attack of phenolic acids. Biotechnol. Bioeng. 2015;112: 1770-1782. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

In an effort to reduce the production cost of biodieseland realizethe lipase recovery of the in situtransesterificationtechnology, a reactor with facile catalyst separation device was developedin this study. Compared with conventional method of biodiesel production,this improved reactive extraction technology can realize not onlythe biodiesel synthesis in a single step, but also the separationof immobilized lipases from the oilseed residues easily. This technologymay present a sustainable, economically attractive process for biodieselproduction. J. curcasL. seed, methanol,Lipozyme TL IM, and cosolvent n-hexane were usedin this study. The effect of various process parameters on the yieldof fatty acid methyl esters (FAMEs) was investigated. The highestFAMEs yield of 90.6% could be achieved under the optimum conditions: n-hexane/seed ratio of 3.5:1 mL/g, methanol/oil molar ratioof 6:1, 15% (w/w) of Lipozyme TL IM, reaction temperature of 45 °C,water content of 1.0%, and reaction time of 12 h. The lipase couldmaintain more than 40% of its initial activity after 13 batches operationunder optimal reaction conditions. This simple in situtransesterification technology with facile catalyst separation devicecan be a potential route for biodiesel production, which may greatlyreduce the processing steps and costs. [ABSTRACT FROM AUTHOR]

Background: Phenolic aldehydes generated from lignocellulose pretreatment exhibited severe toxic inhibitions on microbial growth and fermentation. Numerous tolerance studies against furfural, 5-hydroxymethyl-2-furaldehyde (HMF), acetate, and ethanol were reported, but studies on inhibition of phenolic aldehyde inhibitors are rare. For ethanologenic strains, Zymomonas mobilis ZM4 is high in ethanol productivity and genetic manipulation feasibility, but sensitive to phenolic aldehyde inhibitors. Molecular mechanisms of tolerance for Z. mobilis toward phenolic aldehydes are not known., Results: We took the first insight into genomic response of Z. mobilis ZM4 to the phenolic aldehyde inhibitors derived from lignocellulose pretreatment. The results suggest that the toxicity to cells is caused by the functional group of phenolic aldehyde, similar to furfural and HMF, rather than aromatic groups or phenolic hydroxyl groups. Transcriptome response against 4-hydroxybenzaldehyde, syringaldehyde, and vanillin, representing phenolic groups H, S, and G, respectively, was investigated. The atlas of the important genes responsible for significantly enhanced and repressed genes at the genomic level was illustrated. 272 genes with twofold greater expressions than non-treated controls and 36 gene clusters in response to challenges of these phenolic aldehydes were identified. Several reductases encoded by ZMO1116, ZMO1696, and ZMO1885 were found to play the key roles in reducing phenolic aldehydes into the corresponding phenolic alcohols. Reduction of phenolic aldehydes by overexpression of ZMO1116, ZMO1696, and ZMO1885 in Z. mobilis ZM4 resulted in the increased inhibitor conversion and ethanol productivity, especially for 4-hydroxybenzaldehyde and vanillin. Several transporter genes such as ZMO0282, ZMO0283, ZMO0798, ZMO0799, and ZMO0800 was also displayed significantly increased expressions against the phenolic aldehydes., Conclusions: The genes encoding reductases are with potentials on phenolic aldehydes-tolerant genes contributing to the reduction of phenolic aldehydes into the corresponding phenolic alcohols forms for Z. mobilis ZM4. Overexpression of the key genes improved the conversion ratio and ethanol productivity of 4-hydroxybenzaldehyde and vanillin with high toxicity. New knowledge obtained from this research aids understanding the mechanisms of bacterial tolerance and the development of the next-generation biocatalysts for advanced biofuels production.