Bioethanol production from lignocellulosic raw-materials requires the hydrolysis of carbohydrate polymers into a fermentable syrup. During hemicellulose with dilute acid, variety toxic compounds are produced such as soluble aromatic aldehydes lignin and furfural pentose destruction. In this study, we have investigated toxicity representative (furfural, 5-hydroxymethlyfurfural, 4-hydroxybenzaldehyde, syringaldehyde, vanillin) inhibitors growth ethanol by ethanologenic derivatives Escherichia...

The hydrolysis of hemicellulose to monomeric sugars by dilute acid is accompanied the production inhibitors that retard microbial fermentation. Treatment hot hydrolysate with Ca(OH)(2) (overliming) an effective method for detoxification. Using ethanologenic Escherichia coli LY01 as biocatalyst, our results indicate optimal lime addition detoxification varies and depends on concentration mineral acids organic in each hydrolysate. This optimum was shown be readily predicted basis titration 2 N...

Hemicellulose syrups from dilute sulfuric acid hydrolysates of hemicellulose contain inhibitors that prevent efficient fermentation by yeast or bacteria. It is well known the toxicity these hydrolysate can be ameliorated optimized "overliming" with Ca(OH)2. We have investigated optimization overliming treatments for sugar cane bagasse (primarily pentose sugars) using recombinant Escherichia coli LY01 as biocatalyst. A comparison composition before and after optimal revealed a substantial...

The technology is available to produce fuel ethanol from renewable lignocellulosic biomass. current challenge assemble the various process options into a commercial venture and begin task of incremental improvement. Current designs for lignocellulose are far more complex than grain processes. This complexity results in part substrate biological limitations catalyst. Our work at University Florida has focused primarily on genetic engineering Enteric bacteria using genes encoding Zymomonas...

Lignocellulose can be readily hydrolyzed into a mixture of sugars using dilute mineral acids. During hydrolysis, variety inhibitors are also produced which include aromatic alcohols from lignin and furfuryl alcohol pentose destruction. Seven compounds were investigated individually in binary combinations (catechol, coniferyl alcohol, guaiacol, hydroquinone, methylcatechol, vanillyl alcohol). Aromatic inhibited ethanol production xylose batch fermentations primarily by inhibiting the growth...

In comparison with phototrophic growth, heterotrophic conditions can significantly increase growth rates, final cell number and mass in microalgae cultures. Neochloris oleoabundans is a microalga of biotechnological interest that accumulates lipids under nitrogen-limited conditions. Heterotrophic flask culture experiments were conducted to identify carbon sources be metabolized by N. oleoabundans, bioreactor batch fed-batch (nitrate pulse additions) cultures supplemented glucose performed...

Several microalgal species are capable of growing heterotrophically, exhibiting considerable metabolic versatility and flexibility. As demonstrated in this review, heterotrophic conditions can enhance the biomass concentration by as much 25-fold compared with phototrophic conditions. Currently, these types cultivation economically feasible only for high-value products, including polyunsaturated fatty acids (PUFAs), pigments, antioxidants, polysaccharides, food aquaculture feed from carbon...

Abstract In Escherichia coli, the uptake and phosphorylation of glucose is carried out mainly by phosphotransferase system (PTS). Despite efficiency transport PTS, required consumption 1 mol phosphoenolpyruvate (PEP) for each internalized represents a drawback some biotechnological applications where PEP precursor desired product. For this reason, there considerable interest in generation strains that can efficiently non‐PTS mechanism. The purpose work was to study effect different gene...

Abstract A simple method based on UV spectra was developed for the estimation of total furans (furfural and hydroxymethylfurfural) in hemicellulose hydrolysates. hydrolysate contained a single dominant peak at around 278 nm. Approximately two‐thirds this can be attributed to furan absorbance hydroxymethylfurfural). At 284 nm, both furfural hydroxymethylfurfural have equal weight basis. comparison HPLC determinations different samples used develop equation that allows accurate prediction...

ABSTRACT Wild-type Bacillus subtilis ferments 20 g/liter glucose in 48 h, producing lactate and butanediol, but not ethanol or acetate. To construct an ethanologenic B. strain, homologous recombination was used to disrupt the native dehydrogenase (LDH) gene ( ldh ) by chromosomal insertion of Zymomonas mobilis pyruvate decarboxylase pdc alcohol II adhB under control promoter. The values intracellular PDC ADHII enzymatic activities engineered BS35 strain were similar those found Escherichia...

Anthranilate is an aromatic amine used industrially as intermediate for the synthesis of dyes, perfumes, pharmaceuticals and other classes products. Chemical anthranilate unsustainable process since it implies use nonrenewable benzene generation toxic by-products. In Escherichia coli synthesized from chorismate by synthase (TrpED) then converted to phosphoribosyl transferase continue tryptophan biosynthetic pathway. With purpose generating a microbial strain production glucose, E. W3110...

Resveratrol is a plant natural product with many health-protecting effects which makes it an attractive chemical both for academic studies and industrial purposes. However, the low quantities naturally produced by plants as well unsustainable procedures of extraction, purification concentration have prompted biotechnological approaches to produce this in large from renewable sources. None these considered microbial coculture strategy compound. The aim study was prove functionality...

ABSTRACT Replacement of the native fermentation pathway in Escherichia coli B with a homo-ethanol from Zymomonas mobilis ( pdc and adhB genes) resulted 30 to 50% increase growth rate glycolytic flux during anaerobic xylose. Gene array analysis was used as tool investigate differences expression levels for genes involved xylose catabolism parent (strain B) engineered strain (KO11). Of 4,290 total open reading frames, only 8% were expressed at significantly higher level KO11 P < 0.05). In...

We report the cloning of pykA and pykF genes from Escherichia coli, which code for two pyruvate kinase isoenzymes (ATP:pyruvate 2-O-phosphotransferases; EC 2.7.1.40) in this microorganism. These were insertionally inactivated with antibiotic resistance markers utilized to interrupt one or both pyk E. coli chromosome. With these constructions, we able study role biosynthesis.

The aromatic compounds cinnamic acid (CA) and p-hydroxycinnamic (pHCA) are used as flavoring agents well precursors of chemicals. These present in plants at low concentrations, therefore, complex purification processes usually required to extract the product. An alternative production method for these acids is based on use microbial strains modified by metabolic engineering. biotechnological simple sugars like glucose a raw material. However, sustainable should preferably be waste material...