Physiological evaluation of yeast strains under anaerobic conditions using glucose, fructose, or sucrose as the carbon source.

The aim of this study was to evaluate the physiology of 13 yeast strains by assessing their kinetic parameters under anaerobic conditions. They included Saccharomyces cerevisiae CAT-1 and 12 isolated yeasts from different regions in Brazil. The study aimed to enhance understanding of the metabolism of these strains for more effective applications. Measurements included quantification of sugars, ethanol, glycerol, and organic acids. Various kinetic parameters were analyzed, such as specific substrate utilization rate (qS), maximum specific growth rate (µmax), doubling time, biomass yield, product yield, maximum cell concentration, ethanol productivity (PEth), biomass productivity, and CO2 concentration. S. cerevisiae CAT-1 exhibited the highest values in glucose for µmax (0.35 h-1), qS (3.06 h-1), and PEth (0.69 gEth L-1 h-1). Candida parapsilosis Recol 37 did not fully consume the substrate. In fructose, S. cerevisiae CAT-1 stood out with higher values for µmax (0.25 h-1), qS (2.24 h-1), and PEth (0.60 gEth L-1 h-1). Meyerozyma guilliermondii Recol 09 and C. parapsilosis Recol 37 had prolonged fermentation times and residual substrate. In sucrose, only S. cerevisiae CAT-1, S. cerevisiae BB9, and Pichia kudriavzevii Recol 39 consumed all the substrate, displaying higher PEth (0.72, 0.51, and 0.44 gEth L-1 h-1, respectively) compared to other carbon sources.

Chemopreventive effect and induction of DNA repair by oenothein B ellagitannin isolated from leaves of Eugenia uniflora in Swiss Webster treated mice.

Oenothein B (OeB) is a dimeric ellagitannin with potent antioxidative, antitumor, immunomodulatory, and anti-inflammatory properties. Despite the promising activities of OeB, studies examining the genotoxic or protective effects of this ellagitannin on DNA are scarce. Therefore, to further comprehensively elucidate the chemopreventive profile of OeB, the aim of this study was to evaluate the mutagenic and antimutagenic actions of OeB using Salmonella typhimurium strains with the Ames test. The micronucleus (MN) test and comet assay were used to assess the anticytotoxic and antigenotoxic effects of OeB on mouse bone marrow cells following differing treatments (pre-, co-, and post-treatment) in response to cyclophosphamide (CPA)-induced DNA damage. In addition, histopathological analyses were performed to assess liver and kidney tissues of Swiss Webster treated mice. Our results did not detect mutagenic or antimutagenic activity attributed to OeB at any concentration in the Ames test. Regarding the MN test, data showed that this ellagitannin exerted antigenotoxic and anticytotoxic effects against CPA-induced DNA damage under all treatment conditions. However, no anticytotoxic action was observed in MN test after pre-treatment with the highest doses of OeB. In addition, OeB demonstrated antigenotoxic effects in the comet assay for all treatments. Histopathological analyses indicated that OeB attenuated the toxic effects of CPA in mouse liver and kidneys. These findings suggest that OeB exerted a chemoprotective effect following pre- and co-treatments and a DNA repair action in post-treatment experiments. Our findings indicate that OeB protects DNA against CPA-induced damaging agents and induces post-damage DNA repair.

Physiology of yeast strains isolated from Brazilian biomes in a minimal medium using fructose as the sole carbon source reveals potential biotechnological applications.

The aim of this study was to evaluate the kinetic parameters and the production of metabolites of 13 novel yeasts isolated from a distillery and fruits, and Saccharomyces cerevisiae CAT-1, cultivated in fructose-based medium. The yeasts with the highest µ max were obtained from must, Pichia kudriavzevii BB2, P. kudriavzevii BB1, and S. cerevisiae BB9 (0.47-0.49 h-1). S. cerevisiae CAT-1 (3.02 g gDCM-1 h-1), S. cerevisiae BB9 (3.01 g gDCM-1 h-1), and Candida glabrata Recol 41 (2.52 g gDCM-1 h-1) stood out in terms of µ S. C. parapsilosis Recol 29, and Rhodotorula mucilaginosa Recol 03 strains showed the highest Y X/S (0.30 and 0.28 gDCM g-1, respectively). C. glabrata Recol 10 and S. cerevisiae BB9 strains stood out for their higher substrate conversion rates into ethanol (0.44 and 0.41 gEth gS-1, respectively). R. mucilaginosa Recol 03 presented the poorest performance in substrate consumption (0.87 g gDCM-1 h-1), while the strains isolated from must and C. glabrata Recol 10 showed the highest ethanol production and the C. parapsilosis Recol 29 showed the highest biomass conversion.

Biochemical characterization and evaluation of invertases produced from Saccharomyces cerevisiae CAT-1 and Rhodotorula mucilaginosa for the production of fructooligosaccharides.

Invertases are used for several purposes; one among these is the production of fructooligosaccharides. The aim of this study was to biochemically characterize invertase from industrial Saccharomyces cerevisiae CAT-1 and Rhodotorula mucilaginosa isolated from Cerrado soil. The optimum pH and temperature were 4.0 and 70 °C for Rhodotorula mucilaginosa invertase and 4.5 and 50 °C for Saccharomyces cerevisiae invertase. The pH and thermal stability from 3.0 to 10.5 and 75 °C for R. mucilaginosa invertase, respectively. The pH and thermal stability for S. cerevisiae CAT-1 invertase from 3.0 to 7.0, and 50 °C, respectively. Both enzymes showed good catalytic activity with 10% of ethanol in reaction mixture. The hydrolysis by invertases occurs predominantly when sucrose concentrations are ≤5%. On the other hand, the increase in the concentration of sucrose to levels above 10% results in the highest transferase activity, reaching about 13.3 g/L of nystose by S. cerevisiae invertase and 12.6 g/L by R. mucilaginosa invertase. The results demonstrate the high structural stability of the enzyme produced by R. mucilaginosa, which is an extremely interesting feature that would enable the application of this enzyme in industrial processes.

Use of Fourier transform infrared spectroscopy to monitor sugars in the beer mashing process.

Mashing is an enzymatic procedure for the extraction of sugars from malt. It has strong temperature dependence, so monitoring the sugar production is very important for optimization of the brewing process. In this work, Fourier transform infrared spectroscopy (FTIR) was used to monitor three different mashing programs. These all presented high concentrations of maltose and dextrin, enabling their differentiation according to the FTIR absorption bands at 991 and 1022 cm-1, characteristic of maltose and dextrin, respectively. The absorption intensities of these bands were used to monitor the concentrations of the compounds during mashing, and the values were compared to HPLC data. Multivariate analysis of variance was applied to the FTIR absorption intensities in order to separate groups corresponding to the temperature steps of each mashing program. The results demonstrated that infrared absorption offers an alternative to the HPLC method for monitoring the mashing process.

Brazilian savannah fruits: Characteristics, properties, and potential applications.

The Brazilian savannah is the second largest biome of the country, and it displays great biodiversity. The fruits of the native trees have peculiar characteristics and are recognized for their nutritional and therapeutic aspects. However, little is known about their technological and biotechnological potential applications. The existing information concerning these aspects has never been compiled so far. It is known that many of these fruits contain many bioactive compounds of industrial interest, such as carotenoids and phenolic constituents. Another aspect of the fruit is the high fatty acid content of some species. Pequi, bocaiuva, jatoba, baru, amburama, and buriti, for instance, are among those fruits described as being rich in fatty acids, mostly unsaturated ones. Here, we reviewed 18 species from the Brazilian savannah identified to be of interest because of high potencial for sustained medium- and short-term explorations, under the technological and biotechnological aspects, seeking the development of new products from these scarcely studied raw materials.

Genotoxicity and cytotoxicity evaluation of oenothein B and its protective effect against mitomycin C-induced mutagenic action.

The natural product oenothein B (OeB), a dimeric macrocyclic ellagitannin, has a wide range of biological activities, such as antioxidant, anti-inflammatory, anti-viral, antifungal, and antitumor. However, investigations concerning its genotoxicity have not been carried out. This study assessed the cytotoxicity, genotoxicity, and protective effects of oenothein B using in vitro SOS-Inductest and in vivo mouse bone marrow micronucleus (MN) assay through oral and intraperitonial routes. In both assays oenothein B did not produce genotoxic effects in any of doses tested; in contrast, cytotoxic effect in cells was detected only in mice groups treated by both routes and exposed for 24 and 48h. Antigenotoxic and anticytotoxic activities of oenothein B were evaluated using both assays in combination with mitomycin C (MMC), a bioreductive alkylating agent. In the MN assay, a significant reduction was observed in MN frequency in all groups co-treated with MMC and OeB compared to those which received only MMC. Anticytotoxicity was observed in mice groups exposed to OeB and MMC for 24 and 48h. In the SOS-Inductest, oenothein B failed to show antigenotoxic and anticytotoxic effects; thus, it undoubtedly showed an in vivo protective activity against primary DNA damage induced by mitomycin C.

Physiology of Lichtheimia ramosa obtained by solid-state bioprocess using fruit wastes as substrate.

Due to the amount of nutrients available in the agroindustrial wastes, these can be converted into high added-value products by the action of microorganisms in solid-state bioprocesses. The aim of this work was to evaluate the growth physiology and lipase production of the fungus Lichtheimia ramosa using the following Brazilian savannah fruit wastes as substrates: bocaiuva (Acrocomia aculeata), pequi (Caryocar brasiliense), guavira (Campomanesia pubescens), araticum (Annona crassiflora) and seriguela (Spondias purpurea). These residues were triturated, homogenized, adjusted to pH 5.0 and 60 % moisture, sterilized and packaged in plastic tray-type bioreactors before inoculation with 10 % (w/v) of L. ramosa pre-culture medium. The cultivations were conducted in a bacteriological incubator at 30 °C for 40 days. Samples were taken every 5 days and fungi and bacteria contents, proximate composition and lipase activity were evaluated. The maximum fungal counting was observed between 25 and 35 days. L. ramosa reached the stationary phase next to 40 days in all substrates. Mesophilic and psicrophilic aerobic bacteria were not detected. Protein enrichment was obtained for all media, being superior in seriguela residues (391.66 %), followed by pequi (160.04 %), araticum (143.31 %), guavira (102.42 %), and bocaiuva (67.88 %). Lipase production was observed in all cultivated media, except in pequi residues that showed decreasing lipase activity. The higher production was observed in guavira (1.12 U/g) followed by araticum (0.58 U/g), seriguela (0.41 U/g) and bocaiuva (0.21 U/g) waste substrates. It was concluded that the studied fruit wastes have been successfully utilized as substrates for protein enrichment and lipase production with L. ramosa.

Production of enzymes from Lichtheimia ramosa using Brazilian savannah fruit wastes as substrate on solid state bioprocessess

Background: Enzyme production by solid state bioprocess (SSB) using residues as substrate for microorganisms is an alternative for costs reduction and to avoid their disposal into environment. The aim of this work was to evaluate the physiology of the fungus Lichtheimia ramosa in terms of microbial growth and production of amylases, β-glucosidases, carboxymethylcellulase (CMCase), and xylanases, via SSB, utilizing wastes of the Brazilian savannah fruits bocaiuva (Acrocomia aculeata), guavira (Campomanesia pubescens) and pequi (Caryocar brasiliense) as substrate at different temperatures (25, 30, and 35ºC) during 168 hrs. Results: Samples were taken every 24 hrs, which resulted in 8-points kinetic experiments to determine microbiological and enzymatic contents. The best substrate for β-glucosidase activity was pequi waste after 48 hrs at 30ºC (0.061 U/mL). For amylase activity, bocaiuva presented itself as the best substrate after 96 hrs at 30ºC (0.925 U/mL). CMCase activity was higher in guavira waste after 96 hrs at 35ºC (0.787 U/mL). However, the activity was more expressive for xylanase in substrate composed of bocaiuva residue after 144 hrs at 35ºC (1.802 U/mL). Conclusions: It was concluded that best growth condition for L. ramosa is at 35ºC for all substrates and that xylanase is the enzyme with more potential in SSB, considering the studied Brazilian savannah fruit wastes.