Optimization by uniform design U8 (83 ) approach for enhanced caffeine degradation in synthetic wastewater in bioreactor.

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.

Novel caffeine degradation gene cluster is mega-plasmid encoded in Paraburkholderia caffeinilytica CF1.

The widespread use of caffeine in food and drug industries has caused great environmental pollution. Herein, an efficient caffeine-degrading strain Paraburkholderia caffeinilytica CF1 isolated from a tea garden in China can utilize caffeine as its sole carbon and nitrogen source. Combination of chromatographic and spectrophotometric techniques confirmed that strain CF1 adopts N-demethylation pathway for caffeine degradation. Whole genome sequencing of strain CF1 reveals that it has two chromosomes with sizes 3.62 Mb and 4.53 Mb, and a 174-kb mega-plasmid. The plasmid P1 specifically harbors the genes essential for caffeine metabolism. By analyzing the sequence alignment and quantitative real-time PCR data, the redundant gene cluster of caffeine degradation was elucidated. Genes related to catalyzing the N1-demethylation of caffeine to theobromine, the first step of caffeine degradation were heterologously expressed, and methylxanthine N1-demethylase was purified and characterized. Above all, this study systematically unravels the molecular mechanism of caffeine degradation by Paraburkholderia. KEY POINTS: • Caffeine degradation cluster in Paraburkholderia caffeinilytica CF1 was located in mega-plasmid P1. • The whole genome and the caffeine degrading pathway of P. caffeinilytica CF1 were sequenced and elucidated, respectively. • This study succeeded in heterologous expression of methylxanthine N1-demethylase (CdnA) and Rieske oxygenase reductase (CdnD) and illuminated the roles of CdnA and CdnD in caffeine degradation of P. caffeinilytica CF1.

High diversity and variability in the bacterial microbiota of the coffee berry borer (Coleoptera: Curculionidae), with emphasis on Wolbachia.

AIMS: Variation in microbiota of the coffee berry borer (CBB) Hypothenemus hampei was studied. Diversity, structure and function of bacterial communities were compared between eggs vs adults, CBBs from shade coffee vs sun coffee, CBBs from the field vs raised in the laboratory, and CBBs with and without the antibiotic tetracycline. METHODS AND RESULTS: We sequenced the region V4 of the gene 16 S rRNA. Pseudomonadaceae and Enterobacteriaceae, particularly Pseudomonas and Pantoea, dominated microbiotas of the CBB. Comparative functional inferences with PICRUSt suggested that samples from the field were enriched for genes involved in carbohydrate and protein digestion and absorption, while laboratory-reared samples were higher in genes for melanization and caffeine metabolism. CONCLUSIONS: Microbiotas of the CBB were diverse and dominated by the genus Pseudomonas, several species of which have been previously associated with caffeine degradation in this insect. Wolbachia was the only endosymbiont detected with known ability to manipulate host reproduction. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates that stage of development and origin of samples affected the structure and function of the CBB's bacterial communities. This is the first attempt to predict functional significance of the CBB microbiota in nutrition, reproduction and defence.

Identification and characterization of oxidoreductase component (NdmD) of methylxanthine oxygenase system in Pseudomonas sp. NCIM 5235.

Pseudomonas sp. NCIM 5235 is a caffeine-degrading bacterial strain that metabolizes caffeine by sequential demethylation using methylxanthine demethylases. These enzymes belong to the class of two-component Rieske oxygenases and require an oxidoreductase, NdmD, for efficient catalysis. NdmD in Pseudomonas sp. has a unique domain fusion in its N-terminal that is not observed in any other Rieske oxygenase reductases reported so far. In this report, a ~ 1.7 kb ndmD gene from the gDNA of Pseudomonas sp. has been isolated and has been cloned in a pET28a expression vector. Soluble NdmD was over-expressed in Escherichia coli BL21 cells and purified by Ni2+ NTA chromatography. Monomeric molecular mass of the protein was found to be ~ 65 kDa and optimal activity was observed at 35 °C and pH 8.0. It showed broad substrate specificity with highest Kcat/km of 490.8 ± 17.7 towards cytochrome c. To determine the role of N-terminal Rieske domain in its reductase activity, two deletion constructs Δ114NdmD and Δ250NdmD were made. Cytochrome c reductase (ccr) activity of the NdmD constructs and demethylase activity of NdmA in the presence of NdmD constructs showed that there is no significant difference in the catalytic activity of NdmD upon deletion of its N-terminal Rieske domain. However, there might be some functional and evolutionary significance for the fusion of Rieske domain to NdmD and we hypothesize that this domain fusion is an intermediate phase of evolution towards the development of a more efficient enzyme system for xenobiotic degradation.

Paraburkholderia caffeinitolerans sp. nov., a caffeine degrading species isolated from a tea plantation soil sample.

A Gram-stain negative, facultatively anaerobic, non-sporulating, non-motile and rod-shaped bacterium, designated CF3T, was isolated from a tea plantation soil sample and its taxonomic position was determined using polyphasic taxonomy. Strain CF3T displayed optimum growth at 25 °C, pH 5.0 and in the presence of 0-1 % NaCl. Comparative phylogenetic analysis of the 16S rRNA, recA and gyrB gene sequences showed that the isolate belongs to the genus Paraburkholderia, showing high levels of similarity with respect to Paraburkholderia oxyphila OX-01T (98.3, 95 and 93 %, respectively) and Paraburkholderia sacchari IPT101T (98.2, 95 and 95 %, respectively). The predominant ubiquinone was determined to be Q-8, and the polar lipids are phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified amino-phospholipid, three unidentified amino-lipids and three unidentified polar lipids. The major fatty acids were found to be C16:0, C17:0 cyclo, summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c). The DNA G+C content was found to be 63.8 mol% and the DNA-DNA relatedness values between strain CF3T and its two close relatives P. oxyphila OX-01T and P. sacchari IPT101T was 41 and 40 %, respectively. Based on phylogenetic analysis, phenotypic and genotypic data, it is concluded that the isolate represents a novel species of the genus Paraburkholderia, for which the name Paraburkholderia caffeinitolerans sp. nov. is proposed. The type strain is CF3T (= LMG 28688T = CGMCC 1.15105T).

LC-MS/MS-based metabolomic analysis of caffeine-degrading fungus Aspergillus sydowii during tea fermentation.

Natural microorganisms involved in solid-state fermentation (SSF) of Pu-erh tea have a significant impact on its chemical components. Aspergillus sydowii is a fungus with a high caffeine-degrading capacity. In this work, A. sydowii was inoculated into sun-dried green tea leaves for SSF. Metabolomic analysis was carried out by using UPLC-QTOF-MS method, and caffeine and related demethylated products were determined by HPLC. The results showed that A. sydowii had a significant (P < 0.05) impact on amino acids, carbohydrates, flavonoids, and caffeine metabolism. Moreover, A. sydowii could promote the production of ketoprofen, baclofen, and tolbutamide. Along with caffeine degradation, theophylline, 3-methylxanthine, 1,7-dimethylxanthine, 1-methylxanthine, and 7-methylxanthine were increased significantly (P < 0.05) during inoculated fermentation, which showed that demethylation was the main pathway of caffeine degradation in A. sydowii secondary metabolism. The absolute quantification analysis showed that caffeine could be demethylated and converted to theophylline and 3-methylxanthine. Particularly, about 93.24% of degraded caffeine was converted to theophylline, 27.92 mg/g of theophylline was produced after fermentation. PRACTICAL APPLICATION: Aspergillus sydowii could cause caffeine degradation in Pu-erh tea solid-state fermentation and produce theophylline through the demethylation route. Using a starter strain to ferment tea leaves offers a more controllable, reproducible, and highly productive alternative for the biosynthesis of theophylline.