Properties of films obtained from biopolymers of different origins for skin lesions therapy

In this study, the effects of the origin of xanthan used, in combination with chitosan, to prepare films for the treatment of skin lesions were evaluated. The characteristics of the films obtained with xanthan commercially available for the food industry sector and xanthan originated from a fermentation process conducted in a pilot plant were compared. Results showed that the source did not strongly interfere in many of the properties of the films, such as the mechanical properties, cytotoxicity to L929 cells, absorption of simulated body fluid and culture medium, stability in water and saline solution. Hence, even though the properties of biopolymers of different sources might vary, the films prepared with two distinct types of xanthan gum could be considered as potentially safe and similar in terms of relevant characteristics considering the aimed application.

Chemical inhibition of the contaminant Lactobacillus fermentum from distilleries producing fuel bioethanol

The purpose of this study was to determine the Minimum Inhibitory Concentration (MIC) of pure or mixed chemicals for Saccharomyces cerevisiae and Lactobacillus fermentum in the samples isolated from distilleries with serious bacterial contamination problems. The biocides, which showed the best results were: 3,4,4' trichlorocarbanilide (TCC), tested at pH 4.0 (MIC = 3.12 mg/l), TCC with benzethonium chloride (CBe) at pH 6.0 (MIC = 3.12 mg/l) and TCC mixed with benzalkonium chloride (CBa) at pH 6.0 (MIC = 1.53 mg /l). If CBa was used in sugar cane milling in 1:1 ratio with TCC, a 8 times reduction of CBa was possible. This formulation also should be tested in fermentation steps since it was more difficult for the bacterium to develop resistance to biocide. There was no inhibition of S. cerevisiae and there were only antibiotics as an option to bacterial control of fuel ethanol fermentation by S. cerevisiae.

Applications of the hexanic fraction of Agave sisalana Perrine ex Engelm (Asparagaceae): control of inflammation and pain screening

The present study evaluated the anti-inflammatory and analgesic properties of Agave sisalana Perrine in classic models of inflammation and pain. The hexanic fraction of A. sisalana (HFAS) was obtained by acid hydrolysis followed by hexanic reflux. Anti-inflammatory properties were examined in three acute mouse models (xylene ear oedema, hind paw oedema and pleurisy) and a chronic mouse model (granuloma cotton pellet). The antinociceptive potential was evaluated in chemical (acetic-acid) and thermal (tail-flick and hot-plate test) models of pain. When given orally, HFAS (5, 10, 25 and 50 mg/kg) reduced ear oedema (p < 0.0001; 52%, 71%, 62% and 42%, respectively). HFAS also reduced hind paw oedema at doses of 10 mg/kg and 25 mg/kg (p < 0.05; 42% and 58%, respectively) and pleurisy at doses of 10 mg/kg and 25 mg/kg (41% and 50%, respectively). In a chronic model, HFAS reduced inflammation by 46% and 58% at doses of 10 mg/kg and 25 mg/kg, respectively. Moreover, this fraction showed analgesic properties against the abdominal writhing in an acetic acid model (at doses of 5-25 mg/kg) with inhibitory rates of 24%, 54% and 48%. The HFAS also showed an increased latency time in the hot-plate (23% and 28%) and tail-flick tests (61% and 66%) for the 25 mg/kg and 50 mg/kg doses, respectively. These results suggest that HFAS has anti-inflammatory and analgesic properties.

Improvement in RNA extraction from S. cerevisie by optimization in the autolysis and NH3 hydrolysis

The optimization of autolysis of Saccharomyces cerevisiae from brewery was studied aiming at the maximum ribonucleic acid extraction and yeast extract production. The best conditions for yeast autolysis was 55.2ºC, pH= 5.1 and 9.8 percent NaCl for 24h of processing, without the NH3 use. In these conditions, the RNA yield was 89.7 percent, resulting in 51.3 percent of dehydrated yeast extract with 57.9 percent protein. The use of 12.2 percent NH3 at 60ºC after autolysis (8h) and plasmolysis (8h) was not viable due to the reduction in the RNA yield from 89.7to78.4 percent. On the other hand, the thermal shock at 60ºC for 15 minutes prior to autolysis provided an increase in the yield from 89.7 to 91.4 percent. The autolysis, including NaCl plasmolysis in the optimized conditions was efficient, economic and with short time, thus usable for industrial purpose to obtain more valuable products such as yeast extract enriched in RNA and/or protein, for different applications.

Susceptibility of Saccharomyces cerevisiae and lactic acid bacteria from the alcohol industry to several antimicrobial compounds

The antimicrobial effect of several products including commercial formulations currently used in sugar and alcohol factories was determined by adapted MIC (Minimal Inhibitory Concentration) test on Saccharomyces cerevisiae and on natural contaminants Lactobacillus fermentum and Leuconostoc mesenteroides. The MIC test by macrodilution broth method was adapted by formulating of the culture medium with cane juice closely simulating industrial alcoholic fermentation must. Acid penicillin V (MIC 0.10-0.20 µg/ml) and clindamycin (MIC 0.05-0.40 µg/ml) were most effective against bacterial growth in 24 h. Among the chemicals, sulphite (MIC 10-40 µg/ml), nitrite (MIC <117 µg/ml) and copper sulphate (75-300 µg/ml) were the most effective. Zinc and manganese ethylene-bis-dithiocarbamate and dimethyldithiocarbamate did not show good inhibitory effect on bacteria (MIC > 50 µg/ml). Methyldithiocarbamate was efficient only on L. fermentum (MIC 2.5 µg/ml) and S. cerevisiae (MIC 5.0 µg/ml). Thiocianate (MIC 1.2-5.0 µg/ml), bromophenate (MIC 9-18 µg/ml) and n- alkyldimethylbenzylammonium cloride (MIC 1-8 µg/ml) affected S. cerevisiae at similar inhibitory concentration for L. mesenteroides or L. fermentum. Formaldehyde was more effective on bacteria (MIC 11.5 - 23 µg/ml) in both pH (4.5 and 6.5) than yeast (MIC 46-92 µg/ml). Several tested formulated biocides seriously affect S. cerevisiae growth in the similar dosages of the bacterial inhibition, so these products should be avoided or used only in special conditions for the bacterium control of fermentation process. For this step, the control of these contaminants by antibiotics are more suitable and effective.(au)