Solid Fermentation of Bacillus thuringiensis: Method Development

Bacillus thuringiensis (Bt) is a significant bioinsecticidal agent that has been solely produced by liquid fermentation. With the increasing demand of bioinsecticides for organic agriculture, solid fermentation is preferred to enable low-cost and large-scale production of Bt. Therefore, in this study, we attempted to develop a solid state fermentation method to produce Bt by testing different solid substrates and also the effects of water percentage, fermentation time, temperature and seeding rate on the productions of biomass and parasporal crystal bodies (crystal proteins) of the Bt strain PAM33. Corn bran, rice bran and soybean meal are suitable to be utilized as substrates for biomass production. However, crystal proteins are only observed in solid fermentation using soybean meal as the substrate after 6 days of culture. The temperature range of 25-30°C and 10% seeding rate are the most suitable conditions for solid fermentation of strain PAM33 to obtain the bacterial density of approximate 109 CFU/g and the highest quantity of crystal proteins. This study shows that solid fermentation of Bt is feasible and effective to obtain bacterial biomass and crytal proteins by using cheap and available agricultural wastes. Thus, it can be a potential approach to produce the important Bt-based insecticide products for use in organic agriculture.

Application SEM-EDX in Biodegradation of Seafood Wastes by Sponge-Derived Actinomycetes 19C38A1 in Solid Fermentation

Biodegradation of chitin by microorganisms can produce derivative products that have economic value. This research aims to apply SEM-EDX analysis in observing the biodegradation process of seafood industrial waste by actinomycetes. Shrimp shells, cuttlefish bones and fish scales were obtained from the free market. In the early stages, the SEM-EDX spectrum analysis of the substrate showed almost the same carbon, oxygen, and mineral compositions. While the surface of each substrate is quite varied. On the second day of the fermentation, SEM image analysis showed that the growth rate of actinomycetes on each substrate was significantly different. The difference in growth was supported by SEM imaging data which showed damage to the surface of each substrate. Further analysis of the degradation products by HPLC on the second and third days showed the formation of glucosamine. It suspected that actinomycetes can break down shrimp shell waste into glucosamine. This information is very important as the basis for further research related to the optimization of the glucosamine and chitooligosaccharide (COS) production process using the solid fermentation method.

Metarhizium robertsii protease and conidia production, response to heat stress and virulence against Aedes aegypti larvae

Nutritional factors exert significant influence on the growth of entomopathogenic fungi, one of the main agents employed commercially in the biological control of arthropods. Thus, the objective of this work is to optimize the culture medium and solid fermentation time for production of proteases and conidia of Metarhizium robertsii ARSEF 2575 and to evaluate the interference of riboflavin and salts on virulence and resistance to abiotic stress factors. In the first step, nine groups were separated: negative control, positive control, and seven supplementation groups: ammonium nitrate, ammonium chloride, potassium nitrate, sodium nitrate, ammonium sulfate, ammonium phosphate, urea. Sodium nitrate showed significant difference in protease production at the time of 20 days of solid fermentation. Then, different concentrations of sodium nitrate and riboflavin as supplement were evaluated. Response surface methodology demonstrated that riboflavin and sodium nitrate influence proteolytic activity and conidia production, but without synergism. Supplementation of the medium with the optimal concentration of sodium nitrate and riboflavin did not interfere with the germination of conidia without exposure to abiotic stress, but did increase the thermotolerance of conidia. The presence of riboflavin and sodium nitrate at optimal concentrations in the culture medium did not alter fungal virulence with and without exposure to heat stress, varying according to the presence or absence of the supernatant during exposure, evidencing that resistance to heat exposure is multifactorial and dependent on intra- and extracellular factors. Moreover, the supplementation increased the larvicidal activity of the supernatant against Aedes aegypti.

Isolation and Screening of Antagonistic Actinomycetes for Potential Application in The Control of Pathogenic Bacteria in Contaminated Waste

Purpose Organic wastes for agricultural use represents a real agronomic interest but also a risk for public and animal health. Actinomycetes present a potential source of bioactive compounds with multiple applications. Methods Among the 88 isolates of actinomycetes obtained from different samples, we selected a strain identified, thanks to macro- and microscopic characters, as Streptomyces sp. SCM21. This strain showed these potentialities to produce antibacterial metabolites against the pathogenic bacteria tested (S. aureus, B. cereus and S. enteritidis) when cultivated in liquid and solid fermentation. Solid-state fermentation was conducted using sewage sludge as substrate. Results This is the first time that sewage sludge has been used to produce antibacterial metabolites by a strain of actinomycetes in solid-state fermentation. In addition, solid-state fermentation moistened with distilled water gave better antibacterial activity with good sporulation of Streptomyces sp. CSM21. Conclusion The product of solid-state fermentation can be used in the management of contaminated waste to control pathogenic bacteria.

THE FERMENTATION PROCESSING OF TRADITIONAL CHINESE MEDICINE: A SHORT REVIEW

In recent decades, the processing of traditional Chinese medicines has received widespread attention as people's requirements for safety and effectiveness of traditional Chinese medicine have increased. Because of its theory and technical methods, the fermentation processing of traditional Chinese medicines has been distinct from other methods. Based on generalized fermentation, the fermentation of traditional Chinese medicine is based on collection of appropriate traditional Chinese medicinal materials for processing according to the characteristics of the bacteria, so that the original properties of the medicinal materials are modied and the effectiveness is increased. Strong fermentation, liquid fermentation, and two-way solid fermentation are popular fermentation methods. Currently, the study of traditional Chinese medicine's fermentation process has drawn wide interest from academics. In the future, in order to open up new avenues for fermentation and production of traditional Chinese medicine, the selection of fermenting microorganisms and the mode of action of strains in the fermentation phase need to be examined in depth.