Injection of air into the headspace improves fermentation of phosphoric acid pretreated sugarcane bagasse by Escherichia coli MM170

Nieves, Ismael U.; Geddes, C.C.; Mullinnix, Michael T.; Hoffman, R.W.; Tong, Zhaohui; Castro, Eulógio; Shanmugam, K. T.; Ingram, L. O.

doi:10.1016/j.biortech.2011.04.036

Cited by 48 publications

(20 citation statements)

References 23 publications

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“…Incomplete utilization of xylose was observed by Geddes et al (2011). They reported that an increase of inhibitory compound levels, particularly furfural, caused one third of the xylose in sugarcane bagasse hydrolysate to remain unfermented into ethanol by E. coli MM160 after 240 h. Likewise, Nieves et al (2011) improved the xylose consumption by E. coli MM 160's parent, E. coli MM170, by injecting air into the headspace of the fermentation vessel, achieving near complete fermentation after 96 h.…”

Section: Fermentability Tests Of Prehydrolysatesmentioning

confidence: 99%

Design and Optimization of Sulfuric Acid Pretreatment of Extracted Olive Tree Biomass Using Response Surface Methodology

et al. 2017

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Olive tree biomass (OTB) represents an interesting feedstock for bioethanol production. In this study, olive tree pruning was water extracted and pretreated by dilute sulfuric acid to achieve high sugar recoveries from cellulosic and hemicellulosic fractions. Temperature (160 to 200 °C), acid concentration (0 to 8 g acid/100 g extracted raw material), and solids loading (15% to 35% w/v) were selected as operation variables and modified according to a Box-Behnken experimental design. The optimal conditions for the acid pretreatment were 160 °C, 4.9 g sulfuric acid/100 g biomass, and 35% solids loading (w/v), according to multiple criteria that considered the maximization of both the hemicellulosic sugars concentration in prehydrolysate and the overall sugar yield. These optimized conditions yielded a sugar concentration of 79.8 g/L, corresponding to an overall yield of 39.8 g total sugars/100 g extracted OTB. The fermentability of hemicellulosic sugars prehydrolysates from the acid pretreatment was evaluated by Escherichia coli after a detoxification stage by overliming. The prehydrolysates with lower concentrations of toxic compounds were fermented and achieved ethanol yields higher than 80% of the theoretical ethanol yield.

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Section: Fermentability Tests Of Prehydrolysatesmentioning

confidence: 99%

Design and Optimization of Sulfuric Acid Pretreatment of Extracted Olive Tree Biomass Using Response Surface Methodology

et al. 2017

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“…Support for this interpretation comes from several studies in which physical supplying of small amounts of oxygen to fermenting cultures increased the production of ethanol or 2,3-butanediol. [35][36][37][38] The better performance of TS3 compared with TS4 has been attributed to the greater amount of VHb in the latter strain stimulating respiration to a greater extent, thus diverting a greater amount of organic carbon away from fermentation. [22] Another consistency in the results presented here is that the increase in ethanol seems to be entirely (or nearly entirely) from an increase in ethanol produced per unit of biomass.…”

Section: Effects Of Expression Of Vhb; Strains Ts3 Versus Ts4mentioning

confidence: 99%

Efficient ethanol production from potato and corn processing industry waste usingE. coliengineered to expressVitreoscillahaemoglobin

Sümer

Stark

Akbaş

2015

Environmental Technology

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Engineering of ethanologenic E. coli to express the haemoglobin (VHb) from the bacterium Vitreoscilla has been shown to enhance ethanol production by fermentation of pure sugars, sugars from hydrolysis of lignocellulose, components of whey, and sugars from wastewater produced during potato processing. Here, these studies were extended to see whether the same effect could be seen when a mixture of waste materials from processing of potatoes and corn into potato and corn chips were used as sugar sources. Consistent increases in ethanol production coincident with VHb expression were seen in shake flasks at both low aeration and high aeration conditions. The ethanol increases were due almost entirely to increases in the amount of ethanol produced per unit of cell mass. The VHb strategy for increasing fermentation to ethanol (and perhaps other valuable fermentation products) may be of general use, particularly regarding conversion of otherwise discarded materials into valuable commodities.

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“…Jansen et al [71] found optimal 2,3-butanediol productivity by Klebsiella oxytoca at an oxygen supply greater than zero, while Okuda et al [72] and Nieves et al [73] found ethanol production by ethanologenic E. coli to be increased by about 25% by addition of small amounts of air to the cultures. Thus, the effect of VHb on enhancing ethanol levels is presumed to be related to the increase in oxygen supply it provides to cells, although the details of what that mechanism might be are as yet unknown.…”

Section: Metabolic Changes Correlated With Vhb Expressionmentioning

confidence: 99%

The Biochemistry of Vitreoscilla Hemoglobin

Stark

Dikshit²,

Pagilla

2012

Computational and Structural Biotechnology Journal

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The hemoglobin (VHb) from Vitreoscilla was the first bacterial hemoglobin discovered. Its structure and function have been extensively investigated, and engineering of a wide variety of heterologous organisms to express VHb has been performed to increase their growth and productivity. This strategy has shown promise in applications as far-ranging as the production of antibiotics and petrochemical replacements by microorganisms to increasing stress tolerance in plants. These applications of “VHb technology” have generally been of the “black box” variety, wherein the endpoint studied is an increase in the levels of a certain product or improved growth and survival. Their eventual optimization, however, will require a thorough understanding of the various functions and activities of VHb, and how VHb expression ripples to affect metabolism more generally. Here we review the current knowledge of these topics. VHb's functions all involve oxygen binding (and often delivery) in one way or another. Several biochemical and structure-function studies have provided an insight into the molecular details of this binding and delivery. VHb activities are varied. They include supply of oxygen to oxygenases and the respiratory chain, particularly under low oxygen conditions; oxygen sensing and modulation of transcription factor activity; and detoxification of NO, and seem to require interactions of VHb with “partner proteins”. VHb expression affects the levels of ATP and NADH, although not enormously. VHb expression may affect the level of many compounds of intermediary metabolism, and, apparently, alters the levels of expression of many genes. Thus, the metabolic changes in organisms engineered to express VHb are likely to be numerous and complicated.

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Injection of air into the headspace improves fermentation of phosphoric acid pretreated sugarcane bagasse by Escherichia coli MM170

Cited by 48 publications

References 23 publications

Design and Optimization of Sulfuric Acid Pretreatment of Extracted Olive Tree Biomass Using Response Surface Methodology

Design and Optimization of Sulfuric Acid Pretreatment of Extracted Olive Tree Biomass Using Response Surface Methodology

Efficient ethanol production from potato and corn processing industry waste usingE. coliengineered to expressVitreoscillahaemoglobin

The Biochemistry of Vitreoscilla Hemoglobin

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