Citric Acid

Roehr, M.; Kubicek, Christian P.; Komnek, Ji

doi:10.1002/9783527620883.ch9

Cited by 33 publications

(10 citation statements)

References 125 publications

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“…Such syntheses also require handling of hazardous alkoxide precursors and corrosive alkali reagents, and hence research has shifted to the development of greener preparative methods utilizing more environmentally benign chemicals. Citric acid [30] can be considered a biomass-derived carbohydrate and hence a more sustainable reagent for use as a chelating agent in sol-gel chemistry to prepare binary, ternary, and quaternary metal oxides with high degrees of homogeneity [31]. Citrate sol-gels employing metal nitrate precursors are also considered energy efficient syntheses wherein the nitrate acts as an oxidant and the citrate as fuel during the subsequent combustion [31].…”

Section: Introductionmentioning

confidence: 99%

On the Impact of the Preparation Method on the Surface Basicity of Mg–Zr Mixed Oxide Catalysts for Tributyrin Transesterification

et al. 2018

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Mixed metal oxides are promising heterogeneous catalysts for biofuel production from lipids via alcoholysis, however, the impact of solid acidity and/or basicity on reactivity is comparatively poorly understood. Two systematically related families of MgO-ZrO 2 mixed oxide catalysts were therefore prepared by different synthetic routes to elucidate the impact of surface acid-base properties on catalytic performance in the transesterification of tributyrin with methanol. The resulting materials were characterized by TGA-MS, ICP-OES, N 2 porosimetry, XRD, TEM, XPS, DRIFTS, and CO 2 -temperature-programmed desorption (TPD). MgO-ZrO 2 catalysts prepared by both non-aqueous impregnation and citric acid-mediated sol-gel routes exhibit excellent activity and stability. The citrate routes favor highly dispersed MgO and concomitant Lewis acid-base pair formation at the interface with zirconia. However, for both the citrate and impregnation routes, tributyrin transesterification occurs over a common, strongly basic MgO active site.

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Section: Introductionmentioning

confidence: 99%

On the Impact of the Preparation Method on the Surface Basicity of Mg–Zr Mixed Oxide Catalysts for Tributyrin Transesterification

et al. 2018

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“…e.g. [5]). Our records do not permit exact statements, but it appears that increasing the temperature of a fermentation run that had been started at lower temperatures, e.g.…”

Section: Discussionmentioning

confidence: 99%

Citric Acid Fermentation and the Effects of Temperature

Selahzadeh¹,

Roehr²

2003

Acta Biotechnologica

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SummaryThe temperature of the fermentation media heavily affects yields as well as rates of citric acid fermentations. At 26-28°C, more than 40% of the available carbohydrate raw material is wasted, apparently through the respiratory activity of the fungus. At 30-32°C, these losses are decreased to about 10%. The results thus emphasise the economic importance of adequate temperature control in industrial citric acid fermentation.

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“…The main drawback of the traditional mold fermentation such as high sensitivity to trace metals and low production rates might be overcome [16] by using yeast strains [17±19]. Citric acid production by yeast can be considered as a processing substitute for its advantages over Aspergillus niger.…”

Section: Introductionmentioning

confidence: 99%

Comparative studies on citric acid production by Aspergillus niger and Candida lipolytica using molasses and glucose

Pazouki

Felse

Sinha

et al. 2000

Bioprocess Engineering

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Citric acid production by Aspergillus niger NCIM 548 and Candida lipolytica NCIM 3472 has been studied in shake culture using glucose and molasses as carbon sources. Methanol addition (3% v/v) at 40 h of fermentation enhanced the production of citric acid by Aspergillus niger whereas a reduction in citric acid production by Candida lipolytica was observed with addition of methanol. Maximum citric acid concentration of 12 kg/ m 3 was obtained with Aspergillus niger using molasses in the presence of methanol, while maximum citric acid concentration of 8.4 kg/m 3 was obtained with Candida lipolytica using glucose without methanol. It appears that product formation by Aspergillus niger is either nongrowth associated or partially growth associated depending on the substrate. Methanol addition changes the nature of product formation in case of Candida lipolytica.

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Citric Acid

Cited by 33 publications

References 125 publications

On the Impact of the Preparation Method on the Surface Basicity of Mg–Zr Mixed Oxide Catalysts for Tributyrin Transesterification

On the Impact of the Preparation Method on the Surface Basicity of Mg–Zr Mixed Oxide Catalysts for Tributyrin Transesterification

Citric Acid Fermentation and the Effects of Temperature

Comparative studies on citric acid production by Aspergillus niger and Candida lipolytica using molasses and glucose

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