[Show abstract][Hide abstract] ABSTRACT: Agave tequilana fructans are the source of fermentable sugars for the production of tequila. Fructans are processed by acid hydrolysis or by cooking in ovens at high temperature. Enzymatic hydrolysis is considered an alternative for the bioconversion of fructans. We previously described the isolation of Aspergillus niger CH-A-2010, an indigenous strain that produces extracellular inulinases. Here we evaluated the potential application of A. niger CH-A-2010 inulinases for the bioconversion of A. tequilana fructans, and its impact on the production of ethanol. Inulinases were analyzed by Western blotting and thin layer chromatography. Optimal pH and temperature conditions for inulinase activity were determined. The efficiency of A. niger CH-A-2010 inulinases was compared with commercial enzymes and with acid hydrolysis. The hydrolysates obtained were subsequently fermented by Saccharomyces cerevisiae to determine the efficiency of ethanol production. Results indicate that A. niger CH-A-2010 predominantly produces an exo-inulinase activity. Optimal inulinase activity occurred at pH 5.0 and 50 °C. Hydrolysis of raw agave juice by CH-A-2010 inulinases yielded 33.5 g/l reducing sugars, compared with 27.3 g/l by Fructozyme(®) (Novozymes Corp, Bagsværd, Denmark) and 29.4 g/l by acid hydrolysis. After fermentation of hydrolysates, we observed that the conversion efficiency of sugars into ethanol was 97.5 % of the theoretical ethanol yield for enzymatically degraded agave juice, compared to 83.8 % for acid-hydrolyzed juice. These observations indicate that fructans from raw Agave tequilana juice can be efficiently hydrolyzed by using A. niger CH-A-2010 inulinases, and that this procedure impacts positively on the production of ethanol.
Full-text · Article · Nov 2012 · Journal of Industrial Microbiology
[Show abstract][Hide abstract] ABSTRACT: Cysticercosis is a parasitic disease caused by Taenia solium which affects rurally bred pigs and humans in developing countries. The adult tapeworm parasite lives in the humans intestines, where it sheds thousands of eggs. Cysticercosis occurs after eggs are ingested by pigs or humans. In humans, cysticerci may cause neurocysticercosis, the most severe and frequent form of the human disease. In pigs, cysticerci can lodge in different tissues. Deficient hygiene, inadequate feces disposal, outdoor defecation, freely roaming pigs, and inadequate meat inspection promote transmission. Since pigs are indispensable intermediate host, it is conceivable to curb transmission by reducing pig cysticercosis through vaccination. A vaccine against porcine cysticercosis to be extensively used in non-developed countries must not only be immunologically effective, but must also be inexpensive and simple to administrate to millions of rustically bred pigs, which are renewed every year and are dispersed in thousands of villages across large and variable geographic territories. We developed an anti-cysticercosis vaccine (S3Pvac) composed by three peptides originally identified in Taenia crassiceps. The first version of S3Pvac synthetically produced reduced by 50% the percent of infected pigs, and by 97% the number of cysticerci established, as assessed in a field trial. In search of reducing vaccine production costs, a version of S3Pvac recombinantly expressed in filamentous phages was developed. An improved procedure was standardized for its scale-up production and inactivation. S3Pvac-phage reduced by 54% the number of cysticercotic pigs and by 87% the total number of cysticerci, based on necropsy studies, in a field trial that included 1,047 rural pigs of central Mexico. However, the parenteral administration of the vaccine was found to be a major logistic and economic difficulty, limiting its use in yearly nation's wide programs. Such vaccine requires a risky capture of wild roaming pigs by not less than three or four trained persons. On the other hand, an orally administered vaccine would elude these difficulties, since it could be delivered by the pigs' owners when fed. An oral vaccine has additional attractive features, especially for the prevention of mucosally transmitted parasites as Taenia solium. Transgenic plants are ideal systems to produce oral vaccines, since the walls of the plant cells may protect antigenic proteins from digestion in the intestinal tract, enabling them for effective presentation to mucosal-associated lymphoid tissues. Moreover, the expression of foreign proteins in transgenic plants or in cultured plant cells offers an inexpensive system for the massive production of a vaccine. Thus, the S3Pvac peptides were expressed in transgenic embryogenic papaya cells. The vaccine peptides were stably expressed and incorporated into the papaya nuclear genome by particle bombardment. Orally administered S3Pvac-papaya, composed by transgenic embryogenic cell lines pKETc126, pKETc19, and pKETc723, effectively protect against experimental murine cysticercosis and are immunogenic in pigs. A safe, easy and low-cost system based on the culture of the S3Pvac-papaya cell suspension is being optimizing for massively producing the vaccine. Altogether, results point to the feasibility of having a cost-effective oral vaccine field trial conducted in the near future.
[Show abstract][Hide abstract] ABSTRACT: This paper provides macroscopic and histological evidence on the statistically significant protective effects of S3Pvac-phage vaccination against porcine cysticercosis and hydatidosis. The study included 391 rustically bred pigs (187 vaccinated and 204 controls). Vaccination significantly reduced the prevalence of cysticercosis by 61.7%. Vaccination also significantly reduced by 56.1% the prevalence of hydatidosis caused by Echinococcus granulosus in pigs. The presence of the vaccine epitopes in both cestodes is probably involved in the cross-protection observed. Increased inflammation was found in 5% of cysticerci recovered from controls, versus 24% from vaccinated pigs (P<0.01). Hydatid cysts were non-inflammatory in either group. Vaccination was effective to prevent one single disease, but it failed to prevent the simultaneous infections with both parasites in a same pig. The widening of the S3Pvac-phage vaccine protective repertoire to include hydatidosis is a convenient feature that should reduce the prevalence of two frequent zoonoses that affect rustic porcine breading with a single action. Thus, the costs of two different vaccination programs would be reduced to a single one with significant reduction in both zoonoses.
Full-text · Article · Feb 2011 · Veterinary Parasitology
[Show abstract][Hide abstract] ABSTRACT: In search of reducing vaccine production costs', a recombinant M13 phage version of the anti-cysticercosis tripeptide vaccine (S3Pvac) was developed. The efficacy of S3Pvac-Phage vs. placebo was evaluated in a randomized trial that included 1,047 rural pigs in 16 villages of Central Mexico. Three to five months after vaccination 530 pigs were examined by tongue inspection. At 5-27 months of age, 331 pigs (197 vaccinated/134 controls) were inspected at necropsy. Vaccination reduced 70% the frequency of tongue cysticercosis and, based on necropsy, 54% of muscle-cysticercosis and by 87% the number of cysticerci.
[Show abstract][Hide abstract] ABSTRACT: Vaccination of pigs may curtail Taenia solium transmission by reducing the number of cysticerci, the precursors of adult intestinal tapeworms in humans. Several antigen preparations induce protection against porcine cysticercosis in experimental settings but only one subunit vaccine (S3Pvac) has been tested and proved effective in the field against naturally acquired disease. Besides improving of the vaccine's effectiveness, significant reductions in production costs and in the logistics of its administration are necessary for the feasibility of nationwide control programs. This review highlights the development of several versions of S3Pvac aimed to increase effectiveness, reduce costs and increase feasibility by novel delivery systems and alternative routes of administration.