Brewers' spent grain and thin stillage as raw materials in l‐(+)‐lactic acid fermentation

Brewer's spent grain (BSG) hydrolysates were used for l ‐(+)‐lactic acid (LA) fermentation by Lactobacillus rhamnosus ATCC 7469. In this study the effect of the addition of various amounts of thin stillage (TS) in BSG hydrolysate on LA fermentation parameters were evaluated. TS addition significantly increased utilization of glucose by up to 43.0%. In batch fermentation the highest LA concentration and volumetric productivity of 31.0 g/L, and 0.93 g/L/h, respectively, were obtained with the addition of 50% TS. L. rhamnosus cell viability also increased with the addition of 50% TS (by 2.4%). TS addition significantly increased free amino nitrogen concentration (by up to 209%) which is important for bacterial growth. A strong positive correlation between free amino nitrogen and LA concentration was noted. Compared with the results obtained in the batch fermentation (50% TS), significantly higher LA concentration, yield and volumetric productivity (54.8, 1.9 and 4.0%, respectively) were achieved in fed‐batch fermentation with glucose and TS addition. The results suggest that the combination of the by‐products of brewing and bioethanol industries could be suitable for LA production. Copyright © 2017 The Institute of Brewing & Distilling     

Drying of shiitake mushrooms in a vacuum dryer and optimization of the process by response surface methodology (RSM)

Optimization of shiitake mushroom vacuum drying process was the objective of this research. In order to produce dried sample with satisfactory shelf life, response surface methodology was used. Vacuum drying used to accomplish the task was previously described by the authors. The samples were dried at 46–74 °C and 20–580 mbar. As quality indicators of dried product, total solids, water activity, total phenolics, IC₅₀ and total color change were used. Response surface methodology resulted in optimal conditions of 57.1 °C and 100 mbar. In order to verify predictions and adequacy of the second-order polynomial models, separate validation experiments were conducted at optimum conditions. The predicted amount of total solids was 85.40 %, while a_w value was 0.615.     

Glycerolipids as Selective Thrombin Inhibitors from the Fungus Stereum Hirsutum

ABSTRACT

A dry extract of Stereum hirsutum exhibited a significant inhibitory activity on thrombin (34%). A bioassay oriented fractionation of the extract of Stereum hirsutum has led to the isolation of two active fractions. On the basis of spectroscopic data, chemical reactions, and GC-MS analysis, complex mixtures of diacylglycerophospholipids (DAGPs) and diacylglycerols (DGs) have been isolated and identified. Docking studies suggest that some isolated compounds could bind to the thrombin active site in a similar manner as previously reported phosphonate thrombin inhibitors.     

Lipid peroxidative damage on Cisplatin exposure and alterations in antioxidant defense system in rat kidneys: a possible protective effect of selenium

Cisplatin (Cis-diamminedichloroplatinum II, CP) is an important chemotherapeutic agent, useful in the treatment of several cancers, but with several side effects such as nephrotoxicity. The present study investigated the possible protective effect of selenium (Se) against CP-induced oxidative stress in the rat kidneys. Male Wistar albino rats were injected with a single dose of cisplatin (7 mg CP/kg b.m., i.p.) and selenium (6 mg Se/kg b.m, as Na(2)SeO(3), i.p.), alone or in combination. The obtained results showed that CP increased lipid peroxidation (LPO) and decreased reduced glutathione (GSH) concentrations, suggesting the CP-induced oxidative stress, while Se treatment reversed this change to control values. Acute intoxication of rats with CP was followed by statistically significant decreased activity of antioxidant defense enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and glutathione-S-transferase (GST). Treatment with Se reversed CP-induced alterations of antioxidant defense enzyme activities and significantly prevented the CP-induced kidney damage.     

Reductive electrochemical remediation of emerging and regulated disinfection byproducts

Long-term exposure to low concentrations of disinfection byproducts (DBPs) in drinking water has been associated with increased human-health risks of bladder cancer and adverse reproductive outcomes. In this study, we investigated electrochemical reduction utilizing a resin-impregnated graphite cathode for the degradation of 17 DBPs (i.e. halomethanes, haloacetonitriles, halopropanones, chloral hydrate and trichloronitromethane) at low μg L⁻¹ concentration levels. The reduction experiments were potentiostatically controlled at cathode potentials −700, −800 and −900 mV vs Standard Hydrogen Electrode (SHE) during 24 h. At the lowest potential applied (i.e. −900 mV vs SHE), the disappearance of DBPs from the solution after 24 h of reduction was >70%, except for chloroform (32%), 1,1-dichloropropanone (48%), and chloral hydrate (31%). Due to the participation of several removal mechanisms (e.g. electrochemical reduction, adsorption, volatilization and/or hydrolysis) it was not possible to distinguish the removal efficiencies of electrochemical reduction of individual compounds. Adsorption of the more hydrophilic DBPs (i.e. haloacetonitriles, chloral hydrate, and 1,1-dichloropropanone) onto the electrode seems to be affected by the cathode polarization, as the removals observed in the open circuit experiments were significantly higher than the ones obtained in electrochemical reduction under the same conditions. The overall efficiency of reduction was estimated based on the analyses of the released Cl⁻, Br⁻ and I⁻ ions. Nearly complete C-I bond cleavage was achieved at all three potentials applied, and from the theoretically predicted release of I⁻ ions, calculated based on the removed DBPs, 86 ± 9 to 92 ± 1% was measured in the catholyte solution at −700 to −900 mV vs SHE. Debromination efficiencies obtained were 74 ± 3, 79 ± 6 and 68 ± 4% at −700, −800 and −900 mV vs SHE, while for C-Cl bond cleavage the obtained values were 69 ± 1, 72 ± 1 and 76 ± 4%, respectively. Nevertheless, dechlorination efficiencies are to be considered as approximate, since an increase in Cl⁻ concentration was observed in the open circuit experiments due to the hydrolysis of some of the chlorine-containing DBPs. Although the Coulombic efficiencies for DPBs dehalogenation were only 1.9 ± 0.3 (−900 mV vs SHE) -4.1 ± 0.2% (−700 mV vs SHE), relatively low energy consumption of the process was observed, estimated at 72 ± 2 Wh m⁻³ at −900 mV vs SHE for the concentration range of DBPs in this study (i.e. 65.3-129.7 μg L⁻¹). The study demonstrated that reductive electrochemical treatment has the potential to be a modern remediation technology for the removal of low concentrations of halogenated DBPs in water.     

Toxin-producing Ostreopsis cf. ovata are likely to bloom undetected along coastal areas

Mass appearances of the toxic dinoflagellate genus Ostreopsis are known to cause dangerous respiratory symptoms in humans exposed to aerosols. The outbreaks can appear in shallow marine waters of temperate regions around the globe. We followed a massive bloom event on a public beach on the northern Adriatic coast near Rovinj, Croatia. We identified the responsible species and the produced toxins as well as the dynamics of the event with respect to environmental conditions. Ostreopsis cf. ovata appeared in masses from September through October 2010 on a public beach near Rovinj, Croatia but stayed undetected by public health organizations. Respiratory symptoms were observed whenever humans were exposed to substrate samples containing large numbers of Ostreopsis cells. During the mass abundance of O. cf. ovata also exposure to the aerosols on the beach evoked respiratory symptoms in humans. Our measurements showed high cell abundances and high toxin contents with a stable relative contribution of putative Palytoxin and Ovatoxins a-e. Artificial beach structures proved to dramatically reduce settling of the observed Ostreopsis biofilm. Blooms like those reported herein have a high potential to happen undetected with a high potential of affecting the health of coastal human populations. Increased monitoring efforts are therefore required to understand the ecology and toxicology of those bloom events and reduce their negative impact on coastal populations.