Bacteriocin production by Lactobacillus plantarum ST16Pa in supplemented whey powder formulations

Whey, the main by-product of the dairy industry, is frequently disposed of in the environment without any treatment due to the high cost of this process. Alternatively, whey can be used as a medium to culture lactic acid bacteria and produce value-added products such as bacteriocins. In this work, we attempted to improve bacteriocin production by Lactobacillus plantarum ST16Pa in a whey powder formulation supplemented with additional sources of carbon, nitrogen, and vitamin B12 at different levels and varying the agitation intensity according to a Plackett-Burman experimental design. Only the addition of tryptone positively influenced the production of this bacteriocin. The results allowed us to identify a supplemented whey formulation, comprising 150 g/L of whey total solids plus 10 g/L of tryptone and soybean extract, whose fermentation by Lb. plantarum ST16Pa in shake flasks under agitation at 150 rpm led to a cell-free supernatant with an antimicrobial activity against Listeria innocua 6a CLIST 2865 (inhibition zone of 13.23 mm) close to that previously obtained in de Man, Rogosa and Sharpe medium by other authors. These results are significant considering that the same strain cultured in cheese whey did not previously display any antimicrobial activity

Characterization of actinomycetes isolated from water and sediment samples from Tietê River Basin.

A bacia do rio Tietê, é a maior região hidrográfica do Estado de São Paulo e possui biodiversidade pouco explorada. Actinomicetos são produtores de moléculas bioativas e são descritas em ambientes aquáticos. O objetivo deste estudo foi caracterizar e identificar actinomicetos isolados da água e sedimento da bacia do rio Tietê. Nove actinomicetos foram isoladas: 6 do gênero Streptomyces e 3 do gênero Micromonospora. Três dos isolados pertencem a novas espécies. Os demais isolados foram identificados como S. bingchenggensis, S. lavendulae, S. humi e S. gancidicus; M. sediminicula e M. tulbaghiae. Todos as linhagens foram capazes de hidrolisar ao menos um dos substratos lignocelulósicos testados. Todos os isolados do gênero Streptomyces apresentaram atividade antifúngica. Com exceção de 2 isolados, todos os isolados apresentaram atividade antibacteriana, inclusive contra bactérias multiresistentes a antibióticos. Os genomas dos isolados foram anotados por RAST e antiSMASH, e apresentaram clusters de PKS do tipo I, II e III, sideróforos, terpenos, NRPS, ectoínas, fenazinas, lantipeptídeos, butirolactonas e bacteriocinas. Todos os isolados deste estudo apresentaram grande potencial biotecnológico, comprovado in silico e in vitro.The Tietê river basin is the largest hydrographic region of São Paulo and its biodiversity is underexplored. Actinomycetes are known to bioactive molecules, and are described in aquatic environments. The aim of this study was to characterize and identify actinomycetes isolated from water and sediment from the Tietê river basin. Nine strains of actinomycetes were isolated: 6 Streptomyces strains and 3 Micromonospora strains. Three isolates are new species of actinomycetes. The remaining isolates were identified as S. bingchenggensis, S. lavendulae, S. humi and S. gancidicus; M. sediminicula and M. tulbaghiae. All strains could hydrolyse at least one of the lignocellulosic substrates tested. All Streptomyces showed antifungal activity. Except for two strains, all isolates showed antibacterial activity, including against multiresistant bacteria. The genomes of all isolates were annotated by RAST and antiSMASH and showed clusters of: type I, II and III PKS, siderophores, terpenes, NRPS, ectoins, phenazines, lantipeptides, butyrolactones and bacteriocins. All isolates in this study showed a high biotechnological potential, proved by in silico and in vitro methods

Effects of the inoculation of Enterobacter sp. ICB481 on the growth and nitrogen content of sugarcane plantlets submitted to organic and conventional fertilization.

A interação da bactéria diazotrófica Enterobacter sp.ICB481 com plântulas de cana-de-açúcar foi avaliada em culturas com adubação orgânica ou convencional. As plântulas foram separadas em grupos: orgânico, convencional e sem adubação (inoculadas e não inoculadas com a bactéria). Após 60 dias, os fertilizantes orgânico e convencional atuaram de forma semelhante nos parâmetros de crescimento: comprimentos foliar, volume radicular, massas fresca e seca em folhas, concentrações de nitrato, amônio, aminoácidos, proteínas, açúcares e teor de clorofila. O parâmetro de massa fresca radicular foi maior no grupo orgânico. A inoculação de Enterobacter promoveu maior volume e massa fresca radicular nos grupos orgânico e convencional. No grupo sem adubação, a inoculação aumentou todos os parâmetros de crescimento, clorofila total, incremento protéico e conteúdo de nitrogênio.The interaction of diazotrophic bacterium Enterobacter sp. ICB481 in sugarcane plantlets was evaluated in cultures with organic or conventional fertilization. Plantlets were separated into groups: organic, conventional and no fertilization (inoculated or not with the bacterium). After 60 days, the organic and conventional fertilizers presented similar growth parameters for: leaf length, root volume, fresh and dried matter of leaves, concentrations of nitrate, ammonium, amino acids, proteins, sugars and chlorophyll content. The parameter of fresh matter was higher in the organic group. The inoculation of Enterobacter promoted greater root volume and fresh matter in organic and conventional groups. In the group without fertilizer, inoculation increased all growth parameters, chlorophyll, protein and nitrogen content

Screening of polyketide genes from Brazilian Atlantic Forest soil

Soil is a large source of microorganisms with potential to produce bioactive compounds. Since most of them cannot be cultured, metagenomics has become a useful tool in order to evaluate this potential. The aim of this study was to screen biosynthetic polyketide genes (PKS) present in a metagenomic library constructed from a soil sample isolated from the Brazilian Atlantic Forest. The library comprises 5000 clones with DNA inserts between 40 and 50 Kb. The characterization of the biosynthetic gene clusters of these molecules is a promising alternative to elucidate the biotechnological potential of bioactive compounds in microbial communities. The PKS genes were screened using degenerated primers. The positive clones for PKS systems were isolated, and their nucleotide sequences analysed with bioinformatics tools. The screening yielded two positive clones for PKS II genes. Furthermore, variations in the sequences of the PKS II genes from the metagenomic library were observed when compared with sequences of ketosynthases’ databases. With these findings we gain insight into the possible relation between new biosynthetic genes and the production of new secondary metabolites

Screening of polyketide genes from Brazilian Atlantic Forest soil

Soil is a large source of microorganisms with potential to produce bioactive compounds. Since most of them cannot be cultured, metagenomics has become a useful tool in order to evaluate this potential. The aim of this study was to screen biosynthetic polyketide genes (PKS) present in a metagenomic library constructed from a soil sample isolated from the Brazilian Atlantic Forest. The library comprises 5000 clones with DNA inserts between 40 and 50 Kb. The characterization of the biosynthetic gene clusters of these molecules is a promising alternative to elucidate the biotechnological potential of bioactive compounds in microbial communities. The PKS genes were screened using degenerated primers. The positive clones for PKS systems were isolated, and their nucleotide sequences analysed with bioinformatics tools. The screening yielded two positive clones for PKS II genes. Furthermore, variations in the sequences of the PKS II genes from the metagenomic library were observed when compared with sequences of ketosynthases’ databases. With these findings we gain insight into the possible relation between new biosynthetic genes and the production of new secondary metabolites

Screening of polyketide genes from Brazilian Atlantic Forest soil

Soil is a large source of microorganisms with potential to produce bioactive compounds. Since most of them cannot be cultured, metagenomics has become a useful tool in order to evaluate this potential. The aim of this study was to screen biosynthetic polyketide genes (PKS) present in a metagenomic library constructed from a soil sample isolated from the Brazilian Atlantic Forest. The library comprises 5000 clones with DNA inserts between 40 and 50 Kb. The characterization of the biosynthetic gene clusters of these molecules is a promising alternative to elucidate the biotechnological potential of bioactive compounds in microbial communities. The PKS genes were screened using degenerated primers. The positive clones for PKS systems were isolated, and their nucleotide sequences analysed with bioinformatics tools. The screening yielded two positive clones for PKS II genes. Furthermore, variations in the sequences of the PKS II genes from the metagenomic library were observed when compared with sequences of ketosynthases’ databases. With these findings we gain insight into the possible relation between new biosynthetic genes and the production of new secondary metabolites