Production of carotenoid sarcinaxanthin by Kocuria palustris isolated from Northeastern Brazil Caatinga soil and their antioxidant and photoprotective activities

BACKGROUND This study aimed to produce carotenoids of two bacterial strains obtained and isolated from Caatinga soil in Northeastern Brazil and to evaluate their antioxidant and photoprotective activities. The morphological identification of bacteria was performed by Gram staining and molecularly confirmed through the 16S rRNA gene. The production of carotenoids was performed on two 23 factorial designs to analyze the influence of independent variables (temperature range, luminosity, agitation, spiral presence, and bacterial isolate type) for maximum carotenoid yield. The selected condition has been transferred to a bioreactor (10L). The identification of carotenoids was performed by liquid chromatography (HPLC) and mass spectrometry (LC-MS). Antioxidant activity was determined by inhibiting the bcarotene/linoleic acid system and the effectiveness as sunscreen was measured through its sun protection factor (SPF). RESULTS The results revealed that the isolates FT-7.22 and FT-5.12 were identified as Kocuria palustris; producers of a rare C50 carotenoid sarcinaxanthin. This is the first report on the production of carotenoids by this species from the Caatinga Domain. The pigment that was obtained from the Tryptic Soy Broth (TSB) medium in the best conditions of the factorial designs (increased agitation, aeration, and light exposure) exhibited a significant increase in the carotenoid production. The isolated FT-7.22 reached a higher sarcinaxanthin concentration (112,480 lg/L), and it exhibited promising antioxidant (76.53 ± 0.09%) and photoprotective activities (SPF = 9.36 ± 0.52). CONCLUSIUON This study demonstrated the ability of K. palustris to produce carotenoid sarcinaxanthin with antioxidant and photoprotective activities so that it can be applied in cosmetic formulations. How to cite: Mendes-Silva TCD, Vidal EE, de Souza RFR, et al. Production of carotenoid sarcinaxant

First identification of Tn916-like element in industrial strains of Lactobacillus vini that spread the tet-M resistance gene.

The open process used to ferment sugar cane juice or molasses to produce ethanol fuel is prone to contamination by bacterial cells of different species, in particular Lactobacilli. The situation can be exacerbated by the emergence of resistant cells to industrial antibiotics that are normally used to combat this contamination. In this work, two Lactobacillus vini isolates from ethanol distilleries were identified and found to be resistant to doxycycline, a tetracycline derivative, although sensitive to other antibiotics tested. The identification of these isolates was confirmed by sequencing the pheS gene and their clonal origin was shown by PCR-fingerprinting analysis. Moreover, the isolates were shown to carry the transposable element Tn916 that harboured the tet-M gene. Furthermore, conjugation experiments showed that both isolates were capable of transferring this element, and as a result, the tet-M gene, to Enterococcus faecalis reference strain. Finally, the identification of tetracycline resistance in the same distilleries in other Lactobacilli, suggested that inter-species transfer of antibiotic resistance may be occurring in the industrial environment, and thus impairing the efficiency of the antibiotic treatment and causing serious health concerns.

The consequences of Lactobacillus vini and Dekkera bruxellensis as contaminants of the sugarcane-based ethanol fermentation.

This work describes the effects of the presence of the yeast Dekkera bruxellensis and the bacterium Lactobacillus vini on the industrial production of ethanol from sugarcane fermentation. Both contaminants were quantified in industrial samples, and their presence was correlated to a decrease in ethanol concentration and accumulation of sugar. Then, laboratory mixed-cell fermentations were carried out to evaluate the effects of these presumed contaminants on the viability of Saccharomyces cerevisiae and the overall ethanol yield. The results showed that high residual sugar seemed the most significant factor arising from the presence of D. bruxellensis in the industrial process when compared to pure S. cerevisiae cultures. Moreover, when L. vini was added to S. cerevisiae cultures it did not appear to affect the yeast cells by any kind of antagonistic effect under stable fermentations. In addition, when L. vini was added to D. bruxellensis cultures, it showed signs of being able to stimulate the fermentative activity of the yeast cells in a way that led to an increase in the ethanol yield.