Facile One-step Redox Synthesis of Bi2o2co3/bi2o3/bi Ternary Photocatalyst Without Additional Carbon Source

Construction of heterojunction and decoration of cocatalyst are two vital strategies to accelerate migration of charge carriers. However, the fabrication routs of multi-composites are usually complex and expensive. In this work, Bi2O2CO3/Bi2O3/Bi ternary composite was fabricated via a facile one-step redox reaction. Ethylene glycol was selected as the solvent during the whole reaction process. Moreover, ethylene glycol as an excellent reductant can reduce Bi3+ into metallic Bi0 and itself is oxidized to CO32-, which would react with Bi2O3 to generate Bi2O2CO3 without additional carbon source. Component proportions in ternary composites were optimized by the control of the ratios of raw materials. Under simulate solar light, Bi-based ternary composites exhibited enhanced photodegradation efficiencies for multifarious pollutants in comparison with single and binary samples. The enhanced photocatalytic activities were ascribed to accelerated migration rate of charge carriers owing to the construction of heterojunction and decoration of cocatalyst.

Increasing Chitinase Activity of Serratia marcescens PT-6 through Optimization of Medium Composition

Chitin hydrolysate is one of the value added product derived from shrimp shell waste. Production of chitin hydrolysate using biological process offers an environmental friendly method compared to chemical process. Serratia marcescens PT-6, a gram negative chitinolytic bacterium isolated from shrimp pond sediment, shows good activity in hydrolyzing chitin. This study aimed to improve the chitinase activity of S. marcescens PT-6 culture by optimizing the component of chitin-containing medium (additional nitrogen source, additional carbon source, and colloidal chitin). The optimization of chitinase by S. marcescens PT-6 culture was done using one variable at a time method. The sequence of the research were to optimize 1) the type of additional carbon source (glucose, lactose, sucrose, and starch), 2) the type of additional nitrogen source (yeast extract, peptone, ammonium sulphate, and ammonium chloride), 3) the concentration of colloidal chitin (0.5; 1; 1.5; 2; and 2.5%), and 4) the concentration of the additional carbon and nitrogen source. The culture of S. marcescens PT-6 was incubated in colloidal chitin medium at 30 oC and chitinase activity from culture supernatant was analyzed. The results showed that starch gave the highest chitinase activity compare to other carbon source, meanwhile yeast extract was chosen as the best nitrogen source among others. The combination of 1.5% colloidal chitin with 0.5% starch and 0.1% yeast extract in medium increased the chitinase activity of S. marcescens PT-6 to 0.021 U/ml. These results indicated that an appropriate medium composition could increase the chitinase activity produced by S. marcescens PT-6 culture.

Mass Spectrometry Reveals Molecular Structure of Polyhydroxyalkanoates Attained by Bioconversion of Oxidized Polypropylene Waste Fragments

This study investigated the molecular structure of the polyhydroxyalkanoate (PHA) produced via a microbiological shake flask experiment utilizing oxidized polypropylene (PP) waste as an additional carbon source. The bacterial strain Cupriavidus necator H16 was selected as it is non-pathogenic, genetically stable, robust, and one of the best known producers of PHA. Making use of PHA oligomers, formed by controlled moderate-temperature degradation induced by carboxylate moieties, by examination of both the parent and fragmentation ions, the ESI-MS/MS analysis revealed the 3-hydroxybutyrate and randomly distributed 3-hydroxyvalerate as well as 3-hydroxyhexanoate repeat units. Thus, the bioconversion of PP solid waste to a value-added product such as PHA tert-polymer was demonstrated.

The effect of 2′-fucosyllactose on simulated infant gut microbiome and metabolites; a pilot study in comparison to GOS and lactose

Human milk oligosaccharides (HMOs) shape gut microbiota during infancy by acting as fermentable energy source. Using a semi-continuous colon simulator, effect of an HMO, 2′-fucosyllactose (2′-FL), on composition of the infant microbiota and microbial metabolites was evaluated in comparison to galacto-oligosaccharide (GOS) and lactose and control without additional carbon source. Data was analysed according to faecal sample donor feeding type: breast-fed (BF) or formula-fed (FF), and to rate of 2′-FL fermentation: fast or slow. Variation was found between the simulations in the ability to utilise 2′-FL. The predominant phyla regulated by 2′-FL, GOS and lactose were significant increase in Firmicutes, numerical in Actinobacteria, and numerical decrease in Proteobacteria compared to control. Verrucomicrobia increased in FF accounted for Akkermansia, whereas in fast-fermenting simulations Actinobacteria increased with trend for higher Bifidobacterium, and Proteobacteria decrease accounted for Enterobacteriaceae. Short-chain fatty acids and lactic acid with 2′-FL were produced in intermediate levels being between ones generated by the control and GOS or lactose. In 2′-FL fast-fermenting group, acetic acid specifically increased with 2′-FL, whereas lactose and GOS also increased lactic acid. The results highlight specificity of 2′-FL as energy source for only certain microbes over GOS and lactose in the simulated gut model.