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The production of biomass and biopolyesters (polyhydroxyalkanoates) by the marine bacterium Saccharophagus degradans from: glucose, starch, glucosamine, and xylose were studied. The effect of yeast extract, trace elements, vitamins, and initial concentration of each carbon source on biomass production was evaluated. The addition of yeast extract, together with trace elements, increased the biomass production by 5- fold, obtaining the maximum values when using an initial substrate concentration of 20 g/L for: starch, 8.61; glucosamine, 7.06; and xylose, 4.47 (g dry cell weight/ L). From glucose at 40 g/L the maximum biomass production was 9.07 g/L. Next, the biopolymer production under nutrient-limiting conditions (by N, P, S and Mg) was investigated, as well as the ability of S. degradans to produce copolymers from precursors. The biopolyester produced in all cases was poly(3-hydroxybutyrate) (PHB). Different accumulation percentages (g PHB/100 g biomass) were achieved depending on the carbon source used: glucose, 27.72; starch, 18.11; glucosamine 3.33; there was not biopolymer accumulated from xylose. Finally, the PHB produced from each carbohydrate was characterized, presenting molecular weights between 53 and 58 KDa, and fusion temperatures between 164 and 174°C. [ABSTRACT FROM AUTHOR]

The effect of ultrasound on the hydration kinetics and cooking times of six bean varieties was studied. Samples of beans were exposed to ultrasound treatments (10, 20 and 30 min; 40 KHz, 130 W) at 30°C in addition to control treatments. In most cases, the observed maximum moisture content of the dry beans (1.16 ± 0.03 to 1.22 ± 0.02 g/g) after soaking did not vary with the bean variety and ultrasound exposure time. Effective diffusivity significantly increased (P < 0.05) up to 45 times, and the time to obtain the equilibrium moisture content was reduced by 17.6–58.8%, with respect to control treatments, when treated with ultrasound for 30 min. The percentage reduction in cooking time ranged from 5.4 to 43.0. Ultrasound treatment significantly reduced the soaking and cooking times of the bean varieties studied, but the extent of such reduction depended on the bean variety and ultrasound exposure time. [ABSTRACT FROM AUTHOR]