Vanilla juice has been shown empirically to have antifungal activity against some fungal strains; however, there are no activity reported against Alternaria genre. In this work, the chemical profile of vanilla juice was obtained and its antifungal activity against fungal strains from the family Pleosporaceae, isolated from sorghum- and barley-diseased plants, was tested. The strains were identified as Alternaria alternata by their molecular and morphological characteristics. The vanilla juice characterization from Vanilla planifolia pods showed the presence of vanillin, vanillic acid, p-hydroxybenzaldehyde, p-hydroxybenzoic acid, guaiacol, glucovanillin, vanillyl alcohol, and furfural. Vanilla juice showed a fungistatic effect against all A. alternata strains tested in this study and increased the lag time from 50 to 112 h, and no conidia were produced. This result indicates the possible application of vanilla juice as an alternative to control agricultural crops such as barley and sorghum in Mexico.

Scyphophorus acupunctatus Gyllenhal (Coleoptera: Dryophthoridae), which also is known as agave weevil, is distributed across 5 continents. In Mexico, their presence has been reported in 12 states. Many species of Agave (Asparagaceae) are suitable hosts, though not all are equally suitable. Plant infestation can start with either female or male weevils, and their presence can be detected by gummy secretions emanating from feeding sites. The punctures are observed principally in the lower part of the trunk and external roots of the infested plants. Eggs are deposited singly or in clusters of up to 4 eggs at the feeding punctures after tissue decay has begun. The eggs hatch after about 5 d, and young larvae begin to create tunnels in the plant tissue. The larvae display 11 instars, and require about 50 to 90 d for development. The pupae normally require 11 to 14 d. The life cycle lasts between 105 to 137 d depending on the agave species with which the weevil is associated. The active insect can attack during any mo of the yr, although it is more frequent in the rainy season. Scyphophorus acupunctatus dispersion is determined by the attraction of volatile agave compounds. This insect apparently introduces different microorganisms that have been associated with the agave maladies. Plant extracts and seed powders have been assessed as potential botanical insecticides on larvae and pupae, with plant extracts causing mortality of 43 to 53% in larvae and 3 to 15% in pupae, and with seed powders causing 90 to 100% larval mortality. Synthetic insecticides have not been successful because the larvae and adults live inside the plant tissues. Alternative effective control tactics are needed to avoid increased damage and destruction of this important crop.

Ethanol was produced using mucilage juice residues from processed cocoa with Pichia kudriavzevii in batch fermentation. Experimental results showed that maximum ethanol concentration was 13.8 g/L, ethanol yield was 0.50 g-ethanol/g glucose with a productivity of 0.25 g/L h. Likewise, a novel phenomenological model based on the mechanism of multiple parallel coupled reactions was used to describe the kinetics of substrate, enzyme, biomass and product formation. Model parameters were optimized by applying the Levenberg-Marquardt approach. Analysis of results was based on statistical metrics (such as confidence interval), sensitivity and by comparing calculated curves with the experimental data (residual plots). The efficacy of the proposed mathematical model was statistically evaluated using the dimensionless coefficient for efficiency. Results indicated that the proposed model can be applied as a way of augmenting bioethanol production from laboratory scale up to semi-pilot scale.

Online monitoring of fermentation processes is a necessary task to determine concentrations of key biochemical compounds, diagnose faults in process operations, and implement feedback controllers. However, obtaining the signals of all-important variables in a real process is a task that may be difficult and expensive due to the lack of adequate sensors, or simply because some variables cannot be directly measured. From the above, a model-based approach such as state observers may be a viable alternative to solve the estimation problem. This work shows a comparative analysis of the real-time performance of a family of sliding-mode observers for reconstructing key variables in a batch bioreactor for fermentative ethanol production. These observers were selected for their robust performance under model uncertainties and finite-time estimation convergence. The selected sliding-mode observers were the first-order sliding mode observer, the proportional sliding mode observer, and the high-order sliding mode observer. For estimation purposes, a power law kinetic model for ethanol production by Saccharomyces cerevisiae was performed. A hybrid methodology allows the kinetic parameters to be adjusted, and an approach based on inference diagrams allows the observability of the model to be determined. The experimental results reported here show that the observers under analysis were robust to modeling errors and measurement noise. Moreover, the proportional sliding-mode observer was the algorithm that exhibited the best performance.