Characterization of variables related to high stability of raw cow milk.

This research paper analyzes the stability of raw cow milk in the alcohol test and seeks to understand to know the factors that influence milk stability and the occurrence of unstable non-acid milk. Milk samples were collected from the cooling tanks of rural farmers in the state of Paraná twice in summer and twice in winter. The farms were classified according to the production system: pasture with supplementation and feedlot. The following variables were analyzed: stability in the alcohol test, titratable acidity, ionized calcium concentration (iCa), chemical composition of milk, somatic cell count and standard plate count. The results showed that milk stability was greater in winter vs. summer, when the milk contained higher iCa, and in the feedlot vs. pasture system. The Pearson Correlation between variables (ethanol stability, milk composition, iCa, cooling tank temperature, milk volume, number of milking, number of cows milked, fat/protein ratio, distance and travel time) were analyzed. Stability was negatively correlated with iCa concentration and positively with lactose content. Logistic regression of the risk of unstable non-acid milk at 72% alcohol (UNAM72) showed that only iCa and lactose were determinants, while evaluation of the same risk at 78% alcohol revealed iCa, titratable acidity, lactose and milk urea nitrogen as risk factors. Under the dairy farming conditions of Paraná state, the frequency of UNAM72 was low (12.16%) and was higher in summer and in pasture systems with supplementation. In conclusion, in dairy herds bred with high technological level, with adequate nutritional and health management, the frequency of UNAM is low and is related to nutritional management abnd, perhaps, heat stress, factors that alter iCa and lactose levels.

Preparation of Porous Scaffold Based on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) and FucoPol.

This work focused on the development of porous scaffolds based on biocomposites comprising two biodegradable and biocompatible biopolymers: a terpolyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (PHBHVHHx), and the bacterial polysaccharide FucoPol. The PHBHVHHx terpolymer was composed of 3-hydroxybutyrate (55 wt%), 3-hydroxyvalerate (21 wt%), and 3-hydroxyhexanoate (24 wt%). This hydrophobic polyester has low crystallinity and can form elastic and flexible films. Fucopol is a fucose-containing water-soluble polysaccharide that forms viscous solutions with shear thinning behavior and has demonstrated emulsion-forming and stabilizing capacity and wound healing ability. Emulsion-templating was used to fabricate PHA-based porous structures in which FucoPol acted as a bioemulsifier. Compared with the scaffolds obtained from emulsions with only water, the use of FucoPol aqueous solutions resulted in structures with improved mechanical properties, namely higher tensile strength (4.4 MPa) and a higher Young's Modulus (85 MPa), together with an elongation at break of 52%. These features, together with the scaffolds' high porosity and pore interconnectivity, suggest their potential to sustain cell adhesion and proliferation, which is further supported by FucoPol's demonstrated wound healing ability. Therefore, the developed PHBHVHHx:FucoPol scaffolds arise as innovative porous bioactive structures with great potential for use in tissue engineering applications.

Pseudomonas chlororaphis as a multiproduct platform: Conversion of glycerol into high-value biopolymers and phenazines.

Pseudomonas chlororaphis subsp. aurantiaca DSM 19603 was cultivated using glycerol as the sole carbon source for the simultaneous production of medium-chain length polyhydroxyalkanoates (mcl-PHA), extracellular polysaccharide (EPS) and phenazines. A maximum cell dry mass of 11.79 g/L was achieved with a mcl-PHA content of 19 wt%, corresponding to a polymer concentration of 2.23 g/L. A considerably higher EPS production, 6.10 g/L, was attained. Phenazines synthesis was evidenced by the bright orange coloration developed by the culture during the cell growth phase. The mcl-PHA produced by P. chlororaphis was composed mainly of 3-hydroxydecanoate (50 wt%) with lower amounts of 3-hydroxyoctanoate (17 wt%), 3-hydroxytetradecanoate (17 wt%), 3-hydroxydodecanoate (13 wt%) and 3-hydroxyhexanoate (3 wt%). This PHA showed unique thermal features being highly amorphous, with a degree of crystallinity of 27% and a low melting temperature (45.0 °C). The secreted EPS was mostly composed of glucose, glucosamine, rhamnose and mannose, with smaller amounts of three other unidentified monomers. Although the bioprocess can be improved further to define the optimal conditions to produce each bioproduct (mcl-PHA, EPS or phenazines), this study has demonstrated for the first time the ability of P. chlororaphis to simultaneously produce three high-value products from a single substrate.