Free Radicals and Actinobacteria as a Misexplored Goldmine of Antioxidant Compounds.

Free radicals are highly reactive unstable molecules, which can be synthesized in different ways, considered harmful and threatening to humans; these chemical species have free traffic throughout the human body, interacting with biological molecules and human body organ tissues. The interaction between free radicals and biological molecules is the main factor for disease development or pre-existing disease symptoms aggravation. Antioxidants are chemical compounds able to donate electric charge to stabilize molecules such as free radicals. Recent studies have proved the benefits of antioxidants intake in health improvement. In this way, the search for natural sources of antioxidants has become an ascending trend. In this field, the microbial sources are considered poorly explored compared to the numerous amount of other compounds obtained from them, especially from Actinobacteria. The searched literature about Actinobacteria highlights an important capacity of producing natural antioxidants; however, there is a lack of in vivo studies of these isolated compounds. In this review, we gathered information that supports our point of view that Actinobacteria is a truly renewable and superficially explored source of natural antioxidants. Furthermore, our purpose is also to point this limitation and stimulate more researches in this area.

Waste Soybean Oil and Corn Steep Liquor as Economic Substrates for Bioemulsifier and Biodiesel Production by Candida lipolytica UCP 0998.

Almost all oleaginous microorganisms are available for biodiesel production, and for the mechanism of oil accumulation, which is what makes a microbial approach economically competitive. This study investigated the potential that the yeast Candida lipolytica UCP0988, in an anamorphous state, has to produce simultaneously a bioemulsifier and to accumulate lipids using inexpensive and alternative substrates. Cultivation was carried out using waste soybean oil and corn steep liquor in accordance with 2² experimental designs with 1% inoculums (107 cells/mL). The bioemulsifier was produced in the cell-free metabolic liquid in the late exponential phase (96 h), at Assay 4 (corn steep liquor 5% and waste soybean oil 8%), with 6.704 UEA, IE24 of 96.66%, and showed an anionic profile. The emulsion formed consisted of compact small and stable droplets (size 0.2-5 µm), stable at all temperatures, at pH 2 and 4, and 2% salinity, and showed an ability to remove 93.74% of diesel oil from sand. The displacement oil (ODA) showed 45.34 cm² of dispersion (central point of the factorial design). The biomass obtained from Assay 4 was able to accumulate lipids of 0.425 g/g biomass (corresponding to 42.5%), which consisted of Palmitic acid (28.4%), Stearic acid (7.7%), Oleic acid (42.8%), Linoleic acid (19.0%), and γ-Linolenic acid (2.1%). The results showed the ability of C. lipopytica to produce both bioemulsifier and biodiesel using the metabolic conversion of waste soybean oil and corn steep liquor, which are economic renewable sources.

Fungi from a Groundwater-Fed Drinking Water Supply System in Brazil.

Filamentous fungi in drinking water distribution systems are known to (a) block water pipes; (b) cause organoleptic biodeterioration; (c) act as pathogens or allergens and (d) cause mycotoxin contamination. Yeasts might also cause problems. This study describes the occurrence of several fungal species in a water distribution system supplied by groundwater in Recife-Pernambuco, Brazil. Water samples were collected from four sampling sites from which fungi were recovered by membrane filtration. The numbers in all sampling sites ranged from 5 to 207 colony forming units (CFU)/100 mL with a mean value of 53 CFU/100 mL. In total, 859 isolates were identified morphologically, with Aspergillus and Penicillium the most representative genera (37% and 25% respectively), followed by Trichoderma and Fusarium (9% each), Curvularia (5%) and finally the species Pestalotiopsis karstenii (2%). Ramichloridium and Leptodontium were isolated and are black yeasts, a group that include emergent pathogens. The drinking water system in Recife may play a role in fungal dissemination, including opportunistic pathogens.

Filamentous fungi in drinking water, particularly in relation to biofilm formation.

The presence of filamentous fungi in drinking water has become an area worthy of investigation with various studies now being published. The problems associated with fungi include blockage of water pipes, organoleptic deterioration, pathogenic fungi and mycotoxins. Fungal biofilm formation is a less developed field of study. This paper updates the topic and introduces novel methods on fungal biofilm analysis, particularly from work based in Brazil. Further recommendations for standard methodology are provided.

New bioemulsifiers produced by Candida lipolytica using D-glucose and babassu oil as carbon sources

Candida lipolytica IA 1055 produced extracellular biosurfactants with emulsification activity by fermentation using babassu oil and D-glucose as carbon sources. Natural seawater diluted at 50 percent supplemented with urea, ammonium sulfate, and phosphate was used as economic basal medium. The best results were achieved with the YSW-B2 medium, which contained urea, ammonium sulfate, and babassu oil and with YSW-B3 medium, which contained urea, ammonium sulfate, phosphate, and babassu oil, kept under fed batch fermentation for 60 hours with 5 percent of babassu oil. For the two media, the maximum specific growth rates were 0.02 h-1 and 0.04 h-1; the generation times were 34.6 h-1 and 17.3 h-1, and the emulsification activities were 0.666 and 0.158 units, respectively. The molecules of these new bioemulsifiers were contituted of carbohydrates, proteins and lipids.

Detecção de atividade antibacteriana in vitro nos extratos brutos obtidos a partir do plasmódio de Physarella oblonga (Berk. & Curt.) Morgan (Myxomycetes)

Utilizando-se o teste de difusão em meio sólido, detectou-se atividade antibacteriana em extratos de Physarella oblonga (Physaraceae) obtidos a partir de imobilização plasmodial e do plasmódio in natura. Os extratos foram ativos contra Staphylococcus aureus (halos=14 mmf) e Mycobacterium smegmatis (halos=12 mmf e 13 mmf). Menor inibição foi observada frente a Bacillus subtilis (halos=10 mmf e 9 mmf) e Pseudomonas aeruginosa (halos=10 mmf e 8 mmf). Escherichia coli apresentou resistência a todos os extratos testados. O cromatograma evidenciou semelhanças na composição química dos extratos, justificando as similaridades no potencial inibitório de ambos, sendo as substâncias com Rf 0,91 e 0,82, presentes em ambas as amostras, os prováveis inibidores do crescimento bacteriano.

Diffusion solid medium test was used to detect antibacterial activity in Physarella oblonga (Physaraceae) extracts obtained from plasmodial immobilization and in natura plasmodium. The extracts presented activity against Staphylococcus aureus (halos=14 mmf) and Mycobacterium smegmatis (halos=12 mmf e 13 mmf). Slower inhibition was obtained against Bacillus subtilis (halos=10 mmf e 9 mmf) and Pseudomonas aeruginosa (halos=10 mmf e 8 mmf). Escherichia coli presented resistence to all tested extracts. The chromatogram revealed likeness in the chemical composition of the extracts, explaining similarities in inhibitory potential. The substances with Rf 0,91 and 0,82, present in both extracts, could be inhibitor agents of bacterial growth.