The post-fermented tea develops enhanced quality attributes with prolonged storage. In this study, we explored the dynamic changes in sensory characteristics, untargeted and targeted metabolomics, and microbial communities of Rizhao Jinhua white tea (WFB) across different storage years. Storage process reduced bitterness and astringency, while improving overall mellowness. Levels of total polyphenols, amino acids, theaflavins, and thearubigins declined significantly, whereas theabrownin reached its peak at year 5. Among 118 identified differential metabolites, flavonoids exhibited the most pronounced variations. Further targeted quantification of flavonoids revealed catechin, epicatechin, epigallocatechin, quercitrin, and isorhamnetin as key flavor determinants. This was related to glycosylation, hydrogenation, hydroxylation, and hydrolysis reactions occurring during storage. Dominant microbial genera such as Aspergillus and Pseudomonas continuously promoted flavonoids transformations during storage. The outcomes of this research support better approaches to flavor quality optimization in stored Jinhua white tea.
13 July 2023 in Applied Biochemistry and Biotechnology
This work investigated the use of microbial fuel cells (MFCs) for the degradation of polyethylene terephthalate (PET) and the simultaneous generation of electricity. The study implemented two separate single-chamber MFCs, one with a co-culture of Ideonella sakaiensis and Geobacter sulfurreducens (I.S-G.S) and the other with Ideonella sakaiensis and activated sludge (I.S-AS). The effectiveness of microplastic (MP) degradation was assessed based on the electroactivity of the anodic biofilm, the reduction in particle size, and the decrease in PET mass. Both systems achieved a significant reduction in MP size and mass, with the I.S-AS system notably surpassing the I.S-G.S in terms of efficiency and electricity generation. The I.S-AS system achieved a 30% mass reduction and 80% size reduction, along with a peak voltage of 222 mV. The study concludes that MFCs, particularly with the activated sludge co-culture, offer a viable and more environmentally friendly alternative for MP degradation and energy recovery. These findings suggest a promising direction for improving waste management practices and advancing the capabilities of bio-electrochemical systems in addressing plastic pollution. Further research is recommended to optimize the operational conditions and to test a broader range of MP sizes for enhanced degradation efficacy.