The inhibition and eradication of oral biofilms is increasingly focused on the use of plant extracts as mouthwashes and toothpastes adjuvants. Here, we report on the chemical composition and the antibiofilm activity of 15 methanolic extracts of Iris species against both mono-(Pseudomonas aeruginosa, Staphylococcus aureus) and multi-species oral biofilms (Streptococcus gordonii, Veillonella parvula, Fusobacterium nucleatum subsp. nucleatum, and Actinomyces naeslundii). The phytochemical profiles of Iris pallida s.l., Iris versicolor L., Iris lactea Pall., Iris carthaliniae Fomin, and Iris germanica were determined by ultra-high performance liquid chromatography-high-resolution tandem mass spectroscopy (UHPLC-HRMS/MS) analysis, and a total of 180 compounds were identified among Iris species with (iso)flavonoid dominancy. I. pallida, I. versicolor, and I. germanica inhibited both the quorum sensing and adhesion during biofilm formation in a concentration-dependent manner. However, the extracts were less active against maturated biofilms. Of the five tested species, Iris pallida s.l. was the most effective at both inhibiting biofilm formation and disrupting existing biofilms, and the leaf extract exhibited the strongest inhibitory effect compared to the root and rhizome extracts. The cytotoxicity of the extracts was excluded in human fibroblasts. The inhibition of bacterial adhesion significantly correlated with myristic acid content, and quorum sensing inhibition correlated with the 7-β-hydroxystigmast-4-en-3-one content. These findings could be useful for establishing an effective tool for the control of oral biofilms and thus dental diseases.

BACKGROUND The production and consumption of chicken has doubled in the last 17 years. Since slaughter yields range from 70 to 80%, during production various chicken waste residues are generated. One of these residues is waste created after the mechanical separation of chicken meat (W‐MSM). The goal of the circular economy is to manage this waste and transform it into a valuable product. RESULTS W‐MSM was subjected to hydrolysis by the proteolytic enzymes pepsin and papain to obtain bioactive compounds. Papain digestion resulted in several times higher yields of chondroitin sulfate (CS), hyaluronic acid (HA), peptides and amino acids in comparison with pepsin. The hydrolysis conditions were further optimized using the software Design Expert to evaluate the impact of added enzyme, buffer and duration of the hydrolysis. In addition, the scale‐up of this process was verified with 5 kg of W‐MSM and the obtained product contained approximately 77% (w/w) of peptides, 9% (w/w) of CS, 7% (w/w) of HA and 4% (w/w) of amino acids. CONCLUSIONS We tested and optimized the method for evaluating the direct waste from poultry processing and transformed it into a product containing bioactive compounds which can be utilized as an ingredient for improving the properties of feed. © 2019 Society of Chemical Industry

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The freshwater green microalgae, Dictyosphaerium chlorelloides (CCALA 330), has the ability to produce extracellular polysaccharides (EPS). Conditions for optimum growth and EPS overproduction were determined in laboratory-scale tubular photobioreactors (PBR) with a working volume of 300 mL. Multiple limitations in nutrient supply were proven to be an effective method for EPS overproduction. Salinity stress was also applied to the culture, but no significant increase in EPS production was observed. The effects of different nitrogen sources were examined and the microalgae exhibited the fastest growth and EPS production in medium containing ammonium nitrate. Under determined optimal conditions, EPS concentration reached 10 g/L (71% of the total biomass) and a total biomass of 14 g/L at the end of 17 days cultivation. Pilot-scale cultivation was also carried out in a column type airlift photobioreactor (PBR) with a working volume of 60 L. A new and efficient methodology was developed for separating cells from the EPS-containing culture broth. Due to the strong attachment between cells and EPS, high-pressure homogenization was carried out before a centrifugation process. The EPS in the supernatant was subsequently purified using ultrafiltration. The green microalgae Dictyosphaerium chlorelloides may therefore be appropriate for the commercial production of EPS.

An experimental design was ued to optimize the growth of two thraustochytrids, (Schizochytrium limacinum PA-968 and Japonochytrium marinum AN-4), on different nitrogen sources (yeast extract, corn steep liquor, ammonium sulphate) supplemented into saline waste water from the demineralization of cheese whey. Yeast extract was found to be the most suitable complex nutrient source. Nitrogen limitation was found to increase the lipid content in shake flask cultures of thraustochytrids by 12.7–22.4% w/w. The maximum total lipid content (79.1% w/w) and docosahexaenoic acid productivity (0.465 g/l per day) were achieved by J. marinum AN-4 in shake flask cultures. Fed-batch cultures of J. marinum AN-4, under conditions of nitrogen limitation, yielded biomass with a lower lipid content (72.1% wt.) but higher docosahexaenoic acid productivity (1.43 g/l per day). These results provide proof of concept that fed-batch cultivation of thraustochytrids, combined with nitrogen limitation, can be an appropriate strategy for the productive use of saline waste water from the dairy industry.

Different algal species that may have germination inducing activity of holoparasitic broomrape weeds Phelipanche aegyptiaca and P. ramosa seeds were screened through germination bioassay. Green alga produce SL-related compounds. Applied extracts of biomass obtained from the culture of green alga Trebouxia arboricola increased seeds germination of both parasites. An optimatization of the alga extraction led to an increase of P. aegyptiaca germination. Exhausted medium also contained SL-related compounds. The crude extract stimulated the roots length of Arabidopsis thaliana tested in vitro. A similar effect had the algae and GR24 aplications on expression levels of the SL-related genes in Physcomitrella patens. The novel analytical method DESI-MSI detected production of carlactone in the algae. The Trebouxia sp. culture applications in pot experiments had positive effect on growth characteristics of pea plants.

The original version of this article unfortunately contained a mistake. Figures 1 and 2 were interchanged. The correct Figs. 1 and 2 are now given below: