Optimization of Esterase Production in Solid-State Fermentation of Agricultural Digestate

The continuous increase in biogas production poses the need for innovative applications for its by-products. Solid-state fermentation (SSF) has regained attention in the development of several products because of the possibility to use low-cost and easily available substrates, such as organic wastes. SSF represents a valuable process for agricultural digestate valorization in terms of enzyme production. In the present study, cellulase and esterase were produced by Trichoderma asperellum R on a digestate-based substrate in SSF, with esterase as the highest obtained activity. After assessing the effect of light on it, the esterase production in SSF was optimized using response surface methodology. The influence of substrate composition, temperature and humidity on the enzyme production was evaluated on two sets of data generated based on digestate concentration (50% and 70% w/w). The statistical analyses revealed that these parameters affected esterase production only when Trichoderma asperellum grew on substrate containing 50% w/w of digestate. The best esterase activity (264.6 mU/mg total protein) was achieved with the following optimized SSF parameters: 50% digestate, 50% fruits, 10% sawdust, 30 & DEG;C. The current finding of esterase production on digestate-based substrates makes the SSF method presented here a sustainable and completely circular technology

Search for plant-based biofungicides against toxigenic contaminants in barley (Hordeum vulgare L.) forage in hydroponics

The methanolic extracts of Trichoderma asperellum culture filtrates revealed an important inhibition on mycelial growth, sporulation, germination and on the disease reduction on leaf discs of potato inoculated with each of the two isolates of Phytophthora infestans. The 2H-Pyran-2-one-6-pentyl compound could be responsible for the fungicidal activit

Antibacterial biocomposite materials based on essential oils embedded in sol–gel hybrid silica matrices

For the design of antibacterial materials comprising hybrid silica-containing plant oils capable of performing a controlled release of essential oil components, tests of lemongrass, citronella, basil, rosemary, eucalyptus, tea tree, lavender, clove and cinnamon against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Micrococcus luteus showed the essential oil of cinnamon to have the greatest antimicrobial activity. Hybrid organic–inorganic silica materials functionalized with methyl groups (methyl/Si, molar proportions 0.04–1.00), prepared with a sol–gel method, served as host matrices for the essential oil of cinnamon. The antibacterial and release properties of this oil in hybrid silicas were tested with disk diffusion experiments on bacterial cultures. The methyl–silica material with methyl/Si molar ratio 0.75 and load 7.5 % by mass of the encapsulated cinnamon essential oil presented adequate mechanical stability and maintained antibacterial properties for a prolonged period. This work has produced the first application of hybrid organic–inorganic silicas containing an essential oil for the design of antibacterial materials.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones Farmacéuticas (INIFAR)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic