Black tea kombucha: Physicochemical, microbiological and comprehensive phenolic profile changes during fermentation, and antimalarial activity.

This study shows the changes in physicochemical and microbiological composition, and in the phenolic profile of black tea kombucha during fermentation. In addition, the antimalarial potential of the kombucha was evaluated. Ultra-performance liquid chromatography-mass spectrometry multiplex analysis (UPLC-MSE) results revealed a 1.7 log2 fold-change increase in phenolics with the fermentation time, with emphasis on the increase of phenolic acids (0.3 log2 fold-change). Over time there was degradation of flavonoids such as nepetin, hesperidin and catechin 5-O-gallate, to the detriment of the increase in phenolic acids such as gallic acid and cinnamic acid. In addition, black tea kombucha presented antiplasmodic activity against the 3D7 (sensitive chloroquine) and W2 (resistant to chloroquine) strains. Therefore, important changes in the black tea kombucha phenolic profile take place during fermentation, which may help in the development of kombuchas with higher bioactive potential and contribute to a better understanding of the kombucha fermentation process.

Fungal rock phosphate solubilization using sugarcane bagasse.

The effects of different doses of rock phosphate (RP), sucrose, and (NH(4))(2)SO(4) on the solubilization of RP from Araxá and Catalão (Brazil) by Aspergillus niger, Penicillium canescens, Eupenicillium ludwigii, and Penicillium islandicum were evaluated in a solid-state fermentation (SSF) system with sugarcane bagasse. The factors evaluated were combined following a 2(3) + 1 factorial design to determine their optimum concentrations. The fitted response surfaces showed that higher doses of RP promoted higher phosphorus (P) solubilization. The addition of sucrose did not have effects on P solubilization in most treatments due to the presence of soluble sugars in the bagasse. Except for A. niger, all the fungi required high (NH(4))(2)SO(4) doses to achieve the highest level of P solubilization. Inversely, addition of (NH(4))(2)SO(4) was inhibitory to P solubilization by A. niger. Among the fungi tested, A. niger stood out, showing the highest solubilization capacity and for not requiring sucrose or (NH(4))(2)SO(4) supplementation. An additional experiment with A. niger showed that the content of soluble P can be increased by adding higher RP doses in the medium. However, P yield decreases with increasing RP doses. In this experiment, the maximal P yield (approximately 60 %) was achieved with the lower RP dose (3 g L(-1)). Our results show that SSF can be used to obtain a low cost biofertilizer rich in P combining RP, sugarcane bagasse, and A. niger. Moreover, sugarcane bagasse is a suitable substrate for SSF aiming at RP solubilization, since this residue can supply the C and N necessary for the metabolism of A. niger within a range that favors RP solubilization.