Malic acid production through the whole-cell hydration of fumaric acid with immobilised Rhizopus oryzae

Naude, Andre; Nicol, Willie

doi:10.1016/j.bej.2018.05.022

Cited by 20 publications

(17 citation statements)

References 26 publications

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“…Malic acid and citric acid were 8 and 24 times lower of ascorbic acids, respectively. Both are of enormous biological importance, being the two most used acidifiers in the food industry and in beverages [44]. Finally, the detection of lactic acid was noteworthy, although it could not be quantified since it was below its quantification limits.…”

Section: Analysis Of Sugars and Organic Acidsmentioning

confidence: 99%

Ultrasound-Assisted Extraction of Two Types of Antioxidant Compounds (TPC and TA) from Black Chokeberry (Aronia melanocarpa L.): Optimization of the Individual and Simultaneous Extraction Methods

et al. 2019

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Chokeberry (Aronia melanocarpa L.) contains a large number of bioactive compounds, which make of it a highly nutritional and antioxidant food with anti-cancer and anti-inflammatory properties. It has been recently seen its consumption increased because of its interesting composition and properties as a functional food. The ultrasound-assisted extraction method has been optimized, since it is a simple and fast technique to extract phenolic compounds, as well as anthocyanins, not only separately but also simultaneously. Multiple response has been optimized and demonstrated an effectiveness level similar to the individual ones. This represents a considerable reduction in costs, time and work. The optimal conditions for simultaneous extractions were: 54% methanol as extraction solvent at pH 2.72 and 69.4 °C temperature, 70% amplitude, 0.7 s cycle, and 0.5:18.2 g:mL sample mass/solvent volume ratio. The developed methods showed a high precision level with coefficients of variation lower than 5%. The methods were successfully applied to commercial samples. Additionally, the extraction of other compounds of biological interest, such as organic acids and sugars, was also studied.

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Section: Analysis Of Sugars and Organic Acidsmentioning

confidence: 99%

Ultrasound-Assisted Extraction of Two Types of Antioxidant Compounds (TPC and TA) from Black Chokeberry (Aronia melanocarpa L.): Optimization of the Individual and Simultaneous Extraction Methods

et al. 2019

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“…In this study, an immobilised form of R. oryzae is used to investigate the organism's Crabtree characteristics. We have successfully employed the immobilised process in previous studies [24,26,27] and have shown that biomass-medium separation and process up-scaling are considerably simplified when compared to systems with suspended fungal pellets. The initial experimental work explores the effect of oxygen availability in the medium on ethanol formation, while subsequent experiments investigate the effect of glucose limitation on the growth and fumarate production (nitrogen limited) response in order to test the postulated response depicted in Fig.…”

Section: Introductionmentioning

confidence: 99%

Fumarate production with Rhizopus oryzae: utilising the Crabtree effect to minimise ethanol by-product formation

Swart

Roux

Naude

et al. 2020

Biotechnol Biofuels

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Background: The four-carbon dicarboxylic acids of the tricarboxylic acid cycle (malate, fumarate and succinate) remain promising bio-based alternatives to various precursor chemicals derived from fossil-based feed stocks. The double carbon bond in fumarate, in addition to the two terminal carboxylic groups, opens up an array of downstream reaction possibilities, where replacement options for petrochemical derived maleic anhydride are worth mentioning. To date the most promising organism for producing fumarate is Rhizopus oryzae (ATCC 20344, also referred to as Rhizopus delemar) that naturally excretes fumarate under nitrogen-limited conditions. Fumarate excretion in R. oryzae is always associated with the co-excretion of ethanol, an unwanted metabolic product from the fermentation. Attempts to eliminate ethanol production classically focus on enhanced oxygen availability within the mycelium matrix. In this study our immobilised R. oryzae process was employed to investigate and utilise the Crabtree characteristics of the organism in order to establish the limits of ethanol by-product formation under growth and non-growth conditions. Results: All fermentations were performed with either nitrogen excess (growth phase) or nitrogen limitation (production phase) where medium replacements were done between the growth and the production phase. Initial experiments employed excess glucose for both growth and production, while the oxygen partial pressure was varied between a dissolved oxygen of 18.4% and 85%. Ethanol was formed during both growth and production phases and the oxygen partial pressure had zero influence on the response. Results clearly indicated that possible anaerobic zones within the mycelium were not responsible for ethanol formation, hinting that ethanol is formed under fully aerobic conditions as a metabolic overflow product. For Crabtree-positive organisms like Saccharomyces cerevisiae ethanol overflow is manipulated by controlling the glucose input to the fermentation. The same strategy was employed for R. oryzae for both growth and production fermentations. It was shown that all ethanol can be eliminated during growth for a glucose addition rate of 0.07 g L −1 h −1. The production phase behaved in a similar manner, where glucose addition of 0.197 g L −1 h −1 resulted in fumarate production of 0.150 g L −1 h −1 and a yield of 0.802 g g −1 fumarate on glucose. Further investigation into the effect of glucose addition revealed that ethanol overflow commences at a glucose addition rate of 0.395 g g −1 h −1 on biomass, while the maximum glucose uptake rate was established to be between 0.426 and 0.533 g g −1 h −1. Conclusions: The results conclusively prove that R. oryzae is a Crabtree-positive organism and that the characteristic can be utilised to completely discard ethanol by-product formation. A state referred to as "homofumarate production" was illustrated, where all carbon input exits the cell as either fumarate or respiratory CO 2. The highest biomass-based

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“…This is done by using either purified fumarase enzyme, permeabilized or lyophilized cells, or whole cells. Whole‐cell catalysis using S. cerevisiae , Brevibacterium flavus , Brevibacterium ammoniagenes or Rhizopus oryzae seems to be the most widely used method, reaching conversion rates between 80% and ≈100% . The cells are preferably immobilized in suitable materials such as polyacrylamide, alginate or carrageenan to make the process more economic by allowing for catalyst reutilization.…”

Section: Current Industrial Methods For Malic Acid Synthesismentioning

confidence: 99%

Malic acid production from renewables: a review

Kövilein

Kubisch

Cai

et al. 2019

J of Chemical Tech & Biotech

118

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Malic acid derived from fossil resources is currently applied in the food and beverage industries with a medium global production capacity. However, in the transition from a fossil-based to a bio-based economy, biotechnologically produced L-malic acid may become an important platform chemical with many new applications, especially in the field of biopolymers. In this review, currently used petrochemical production routes to DL-malic acid are outlined and insights into possible bio-based alternatives for microbial L-malic acid production are provided. Besides ecological reasons, the possibility to produce enantiopure L-malic acid by microbial fermentation is the biggest advantage over chemical synthesis. State-of-the-art and open challenges concerning production host engineering, substrate choice and downstream processing are addressed. With regard to production hosts, a literature overview is given covering the leading natural production strains of Aspergillus, Ustilago and Aureobasidium, as well as Escherichia coli as the most important engineered recombinant host. The utilization of renewable substrates as an alternative to glucose is emphasized in particular as a key aspect for a competitive bio-based production. Out of the alternative substrates discussed in this review, the industrial side-streams crude glycerol and molasses seem to be most promising for large-scale L-malic acid production.

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Malic acid production through the whole-cell hydration of fumaric acid with immobilised Rhizopus oryzae

Cited by 20 publications

References 26 publications

Ultrasound-Assisted Extraction of Two Types of Antioxidant Compounds (TPC and TA) from Black Chokeberry (Aronia melanocarpa L.): Optimization of the Individual and Simultaneous Extraction Methods

Ultrasound-Assisted Extraction of Two Types of Antioxidant Compounds (TPC and TA) from Black Chokeberry (Aronia melanocarpa L.): Optimization of the Individual and Simultaneous Extraction Methods

Fumarate production with Rhizopus oryzae: utilising the Crabtree effect to minimise ethanol by-product formation

Malic acid production from renewables: a review

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