scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Online measurement of dissolved oxygen in shake flask to elucidate its role on caffeine degradation by Pseudomonas sp.

TL;DR: Higher DO in the medium is required for efficient conversion of caffeine to theobromine which is in agreement that the reaction is oxidative demethylation which will be useful in shaking flask studies and scaling up processes.
Abstract: Caffeine is a plant alkaloid present in the large ratio over other emerging pollutants and it causes serious health effects on overdosage. Microbial degradation of caffeine produces metabolites tha...
Citations
More filters
Journal ArticleDOI
TL;DR: In this paper, a regression model was developed to predict the caffeine degradation rate with oxygen mass transfer coefficient (kLa) and initial biomass concentration, and the optimal conditions of initial biomass and kLa were 0.23g/L and 64.26h−1 respectively.
Abstract: Coffee wastewater poses a serious threat to the environment due to the presence of a large number of toxic compounds which necessitates the importance of developing suitable treatment methodologies. Although there are treatments available to treat the different wastewaters, the presence of caffeine in wastewater interrupts the complete treatment of coffee wastewater. Alternatively, Pseudomonas sp. showed an excellent capacity to withstand coffee wastewater and degrades caffeine completely in shake flask studies. In this study, we scaled up the coffee wastewater treatment to a 1 L in bioreactor and optimized for caffeine degradation using the self-directing optimization technique. Using self-directing optimization maximum degradation rate of 16.73 mg/L.h was obtained at 210 rpm, 1.16 vvm, and 0.383 g/L of initial biomass. A regression model was developed to predict the caffeine degradation rate with oxygen mass transfer coefficient (kLa) and initial biomass concentration. The regression model was solved and the optimal conditions of initial biomass concentration and kLa are 0.23 g/L and 64.26 h−1 respectively. Under those conditions, experiments were performed and maximum degradation rate was 16.9 mg/L.h was obtained, which is in comparison with model prediction (15.2 mg/L.h).

3 citations

Journal ArticleDOI
TL;DR: In this article , optical sensors are employed in single-use shake flasks to measure oxygen, carbon dioxide, pH, and biomass, and optical sensors can also be used to measure carbon dioxide and carbon dioxide.
Abstract: Shake flasks enjoy great popularity due to their ease-of-use and cost-effectiveness. Furthermore, using single-use shake flasks provides additional advantages over reusable glass versions, since they do not need to be cleaned or pre-sterilized. Despite their widespread use, there are, however, clear disadvantages associated with using shake flasks, which are primarily related to the lack of measurement and control capabilities. Therefore, this article discusses how optical sensors can be employed in single-use shake flasks to measure oxygen, carbon dioxide, pH, and biomass.

2 citations

Journal ArticleDOI
TL;DR: This is the first‐ever bioreactor study showing highest caffeine degradation rate in synthetic coffee wastewater with limited experimental runs.
Abstract: Coffee wastewater contains large amounts of caffeine which affects microflora and seed development to great extent. Although several physio‐chemical methods available for caffeine degradation, they are not preferred for large‐scale treatment. In this study, we optimized induced cell concentration, aeration and agitation rate for maximizing caffeine degradation rate in bioreactor using Uniform design. Maximum caffeine degradation rate of 23·59 mg L−1 h−1 was achieved. The reduction in chemical oxygen demand, biological oxygen demand and total organic carbon removal were found to be 72, 78 and 72% respectively. Mathematical model was developed through regression analysis and predicted maximum caffeine degradation rate of 24·2 mg L−1 h−1 under optimal conditions of 0·35 g L−1 biomass, 395 rev min−1 and 1·62 vvm. Experimental validation at optimum condition resulted in 22 mg L−1 h−1 of caffeine degradation rate. This is the first‐ever bioreactor study showing highest caffeine degradation rate in synthetic coffee wastewater with limited experimental runs.
References
More filters
Journal ArticleDOI
TL;DR: The caffeine intakes of the U.S. population was estimated using a comprehensive beverage survey, the Kantar Worldpanel Beverage Consumption Panel, using a nationally representative sample of consumers of caffeinated beverages completed 7-day diaries to assess intakes.

414 citations

Journal ArticleDOI
TL;DR: Theobromine, a methylxanthine derivative present in cocoa, effectively inhibits citric acid‐induced cough in guinea‐pigs in vivo and may form the basis for a new class of antitussive drugs.
Abstract: SPECIFIC AIMSCough is a condition that affects the vast majority of people at some point in their lives and is the most common complaint for which medical attention is sought. Currently, no effective treatment exists. The aim of this study was to investigate the utility of a novel antitussive called theobromine, a methylxanthine derivative present in cocoa and chocolate, on cough and airway sensory nerve function in humans.PRINCIPAL FINDINGS1. Theobromine as a potential antitussiveSeveral synthetic antitussives are characterized by the presence of a 1,2,4-oxadiazole ring in their chemical structure. With the renaissance of the methylxanthine theophylline to treat asthma in the 1970s, a series of novel compounds with an oxadiazolylalkyl substituent at the N7 atom on the basic xanthine skeleton was synthesized and investigated as potential antiasthmatic and antitussive agents.With two of these compounds selected for preclinical testing, 3,7-dihydro-3-methyl-7-/(5-methyl-1,2,4-oxadiazol-3yl)methyl/-1H-purine...

138 citations

Journal ArticleDOI
TL;DR: Development of biodecaffeination techniques using these enzymes or using whole cells offers an attractive alternative to the present existing chemical and physical methods removal of caffeine, which are costly, toxic and non-specific to caffeine.
Abstract: Catabolism of caffeine (1,3,7-trimethylxanthine) in microorganisms commences via two possible mechanisms: demethylation and oxidation. Through the demethylation route, the major metabolite formed in fungi is theophylline (1,3-dimethylxanthine), whereas theobromine (3,7-dimethylxanthine) is the major metabolite in bacteria. In certain bacterial species, caffeine has also been oxidized directly to trimethyl uric acid in a single step. The conversion of caffeine to its metabolites is primarily brought about by N-demethylases (such as caffeine demethylase, theobromine demethylase and heteroxanthinedemethylase), caffeine oxidase and xanthine oxidase that are produced by several caffeine-degrading bacterial species such as Pseudomonas putida and species within the genera Alcaligenes, Rhodococcus and Klebsiella. Development of biodecaffeination techniques using these enzymes or using whole cells offers an attractive alternative to the present existing chemical and physical methods removal of caffeine, which are costly, toxic and non-specific to caffeine. This review mainly focuses on the biochemistry of microbial caffeine degradation, presenting recent advances and the potential biotechnological application of caffeine-degrading enzymes.

105 citations


"Online measurement of dissolved oxy..." refers background in this paper

  • ...Hence, the process can be extended to industrial decaffeination of food, which is currently aided by solvent and supercritical extraction [36,37]....

    [...]

Journal ArticleDOI
TL;DR: This work reports the first report of bacterial N-demethylase genes that enable bacteria to live on caffeine and represent a new class of Rieske oxygenases and have the potential to produce biofuels, animal feed, and pharmaceuticals from coffee and tea waste.
Abstract: The molecular basis for the ability of bacteria to live on caffeine as a sole carbon and nitrogen source is unknown. Pseudomonas putida CBB5, which grows on several purine alkaloids, metabolizes caffeine and related methylxanthines via sequential N-demethylation to xanthine. Metabolism of caffeine by CBB5 was previously attributed to one broad-specificity methylxanthine N-demethylase composed of two subunits, NdmA and NdmB. Here, we report that NdmA and NdmB are actually two independent Rieske nonheme iron monooxygenases with N(1)- and N(3)-specific N-demethylation activity, respectively. Activity for both enzymes is dependent on electron transfer from NADH via a redox-center-dense Rieske reductase, NdmD. NdmD itself is a novel protein with one Rieske [2Fe-2S] cluster, one plant-type [2Fe-2S] cluster, and one flavin mononucleotide (FMN) per enzyme. All ndm genes are located in a 13.2-kb genomic DNA fragment which also contained a formaldehyde dehydrogenase. ndmA, ndmB, and ndmD were cloned as His(6) fusion genes, expressed in Escherichia coli, and purified using a Ni-NTA column. NdmA-His(6) plus His(6)-NdmD catalyzed N(1)-demethylation of caffeine, theophylline, paraxanthine, and 1-methylxanthine to theobromine, 3-methylxanthine, 7-methylxanthine, and xanthine, respectively. NdmB-His(6) plus His(6)-NdmD catalyzed N(3)-demethylation of theobromine, 3-methylxanthine, caffeine, and theophylline to 7-methylxanthine, xanthine, paraxanthine, and 1-methylxanthine, respectively. One formaldehyde was produced from each methyl group removed. Activity of an N(7)-specific N-demethylase, NdmC, has been confirmed biochemically. This is the first report of bacterial N-demethylase genes that enable bacteria to live on caffeine. These genes represent a new class of Rieske oxygenases and have the potential to produce biofuels, animal feed, and pharmaceuticals from coffee and tea waste.

81 citations

Journal ArticleDOI
TL;DR: The crude enzyme preparations obtained from ethanol precipitation were found to be more effective in improving tea leaf fermentation than the purified pectinase enzymes.

68 citations


"Online measurement of dissolved oxy..." refers methods in this paper

  • ..., and absorbances were measured using Shimadzu UV-1800 double beam UV-Vis spectrophotometer [25]....

    [...]