Blanca Aguilar-Uscanga

Spray and freeze drying of human milk on the retention of immunoglobulins (IgA, IgG, IgM)

ABSTRACT Several freeze-drying and spray-drying methods were investigated in relation to the retention of immunoglobulins (Ig) A, IgG, and IgM. Spray drying produced human milk powders with 2% humidity and a good retention of IgG (>88%) and IgM (∼70%). However, only 38% of IgA remained after spray drying. For freeze drying, only the highest heating plate temperature used in this study (40°C) brought IgA content down to 55% in powder with 1.75% residual humidity, whereas milk samples undergoing lower temperatures had higher preservation rates (75% for IgA and 80% for IgG and IgM) and higher residual moisture contents. From these results, it can be concluded that IgA is the most sensitive Ig lost during drying processing of human milk. The best method to generate human milk powders without a significant loss of Ig was thus freeze drying at 30°C heating plate temperature, which accelerated the process compared to lower processing temperatures, but still had good overall Ig retention.

Cancer Chemopreventive, Antiproliferative, and Superoxide Anion Scavenging Properties of Kluyveromyces marxianus and Saccharomyces cerevisiae var. boulardii Cell Wall Components

ABSTRACT This study investigated the cancer chemopreventive, the antiradical, and the antiproliferative properties of polysaccharides extracts from cell wall of Saccharomyces boulardii and Kluyveromyces marxianus. β-glucan, mannan, and chitin were also quantified to identify the most important extract responsible for these biological properties. Soluble and insoluble glucans as well as mannoprotein were extracted from cell wall using single hot-alkaline method. Superoxide anion scavenging (antiradical capacity), NAD(P)H: quinone reductase (QR) (EC 1.6.99.2) induction, and antiproliferative assays were done for the evaluation of biological properties of those extracts. The insoluble glucan from S. boulardii revealed the most relevant biological properties by increasing QR activity and exhibiting the highest growth inhibition against colorectal cancer cells. Moreover, high amount of glucan, high glucan/total sugars ratios, and low chitin/glucan ratios were shown to have an impact on enhancing cancer chemopreventive and antiproliferative properties. To our knowledge, this is the first study that demonstrates QR activity by yeast cell wall components in a dose-dependent manner.

Evaluation of nutrients removal (NO3-N, NH3-N and PO4-P) with Chlorella vulgaris, Pseudomonas putida, Bacillus cereus and a consortium of these microorganisms in the treatment of wastewater effluents

In this research removal of NH3-N, NO3-N and PO4-P nutrients from municipal wastewater was studied, using Chlorella vulgaris, Pseudomonas putida, Bacillus cereus and an artificial consortium of them. The objective is to analyze the performance of these microorganisms and their consortium, which has not been previously studied for nutrient removal in municipal wastewater. A model wastewater was prepared simulating the physicochemical characteristics found at the wastewater plant in Chapala, Mexico. Experiments were carried out without adding an external carbon source. Results indicate that nutrient removal with Chlorella vulgaris was the most efficient with a removal of 24.03% of NO3-N, 80.62% of NH3-N and 4.30% of PO4-P. With Bacillus cereus the results were 8.40% of NO3-N, 28.80% of NH3-N and 3.80% of PO4-P. The removals with Pseudomonas putida were 2.50% of NO3-N, 41.80 of NH3-N and 4.30% of PO4-P. The consortium of Chlorella vulgaris-Bacillus cereus-Pseudomonas putida removed 29.40% of NO3-N, 4.2% of NH3-N and 8.4% of PO4-P. The highest biomass production was with Bacillus cereus (450 mg/l) followed by Pseudomonas putida (444 mg/l), the consortium (205 mg/l) and Chlorella vulgaris (88.9 mg/l). This study highlights the utility of these microorganisms for nutrient removal in wastewater treatments.

Effects of oxygen and nutrients on xylitol and ethanol production in sugarcane bagasse hydrolyzates

The influence of oxygen and nutrient supplementation on xylitol and ethanol production in a synthetic medium and sugarcane bagasse hydrolyzates using Candida tropicalis IEC5-ITV and Saccharomyces cerevisiae ITV01- RD was investigated for evaluation of bioconversion of pentoses and hexoses present in the lignocellulosic biomass. The best oxygen transfer rate (56.05 mg of O2/L/h) and xylitol and ethanol yields (0.67 and 0.47 g/g, respectively) were obtained in a synthetic medium. A yeast extract had a positive effect on xylitol and ethanol production (0.64 and 0.44 g/g, respectively) at a concentration of 1 g/L. C. tropicalis and S. cerevisiae exhibited not previously observed morphological changes depending on the nutrient composition. Use of sugarcane bagasse hydrolyzates requires a good supply of oxygen and addition of a yeast extract to improve xylitol and ethanol production.

Effect of Saccharomyces Boulardii Cell Wall Extracts on Colon Cancer Prevention in Male F344 Rats Treated with 1,2-Dimethylhydrazine

ABSTRACT The effect of Saccharomyces boulardii cell wall extracts on colon cancer prevention in rats treated with 1,2-dimethylhydrazine was investigated. A crude insoluble glucan (0.5 and 1.0 mg/kg/day) and a crude mannoprotein extract (0.3 and 3.0 mg/kg/day) were administered in rats by gavage for 12 weeks along with a high fat low fiber diet whereupon rats were sacrificed and aberrant crypt foci (ACF) were counted in the colon. Moreover, NAD(P)H: quinone reductase (QR) and harmful fecal enzymes (β-glucosidase and β-glucuronidase) were quantified in the liver and in the caecum, respectively. Results showed a reduction in ACF counts, a decreased β-glucuronidase activity and an increased QR activity when rats were treated only with insoluble glucan. While these enzymatic modulations may be constituted one of the mechanisms that is responsible for the reduction of ACF counts observed, the reduction of ACF counts caused by insoluble glucan should be addressed, at least, as a biomarker of their cancer-prevention properties. To our knowledge, this is the first study demonstrated that crude cell wall extract obtained from S. boulardii could have a potential role in colon cancer prevention in vivo by revealing the potential implication of QR and β-glucuronidase modulation.