The genus Arthrospira comprises a group of filamentous multicellular cyanobacteria and can be used for animal feed and human food. Solid state fermentation or cultivation (SSF) involves the use of a culture medium composed of solid material with given moisture content. No studies have been published about the cultivation of microalgae or cyanobacteria on solid medium. Furthermore, although sugar-cane bagasse is used as source of energy in alcohol distilleries in Brazil, the excess could be a support to photosynthetic microorganism growth. The experimental design methodology was used to evaluate the protein production by Arthrospira platensis under SSF using sugarcane bagasse as support, taking into account the moisture content of the medium, light intensity and inoculum concentration. Moisture was found to have a strong influence on the performance of the process. The best conditions were: moisture of 98.8%; inoculum concentration of 0.15 g biomass·kg wet culture medium−1 and light intensity of 6.0 klx.

ABSTRACT. The bacteria Bacillus thuringiensis var. israelensis (Bti) generates certain toxins with pesticide action, which can be used on the control of transmissible diseases by culicides, specially Aedes aegypti, the dengue vector. This biopesticide has been produced by submerged fermentation and, in Brazil, this production has been made by very little research centers and, more recently, by a unique small enterprise. For the implementation of a viable vectors control program through biopesticides, some studies about culture media are essential in order to join efficiency and low costs. In this way, agroindustrial wastes or by-products have been used as a nutrient source for the culture media production. In this study, corn steep liquor, a corn industrial processing by-product and tryptose, both with / without sugar addition, were compared as culture media. Cellular growth was evaluated by optical density at 620 nm, spore production by total viable cell count and LC 50 by bioassays against 4 th instar larvae. Among the four examined substrates, the medium composed by glucose plus corn steep liquor presented the best spore production and bioassay results.Keywords: biological control, fermentation process, agroindustrial waste.Avaliação de dois diferentes meios de cultura para o desenvolvimento de biopesticidas à base de Bacillus thuringiensis e sua aplicação em larvas de Aedes aegypti RESUMO. Visando obter alternativas de meio de cultura de baixo custo para a produção de um biopesticida a partir de Bacillus thuringiensis var. israelensis (Bti), que possua ação efetiva contra larvas de Aedes aegypti (Ae. aegypti), vetor da dengue, foi feita uma comparação entre a eficiência de produtos à base de Bti obtidos através de um meio de cultura tradicionalmente utilizado em pesquisas (triptose) e um subproduto agroindustrial, proveniente de uma indústria de processamento de milho ("milhocina"). Para tanto, estes meios foram inoculados com 2 x 10 2 células mL -1de Bti e incubados por 120 horas, retirando-se amostras periódicas, até 48 horas, para avaliar o crescimento celular (620 nm) e o pH do sistema. Ao final do processo, foi avaliada a quantidade de esporos (por contagem em placas) e a CL 50 (com larvas de 4º instar), expressa como diluição do caldo final. Os resultados indicam uma melhor eficiência do meio "milhocina"-glicose (CL 50 = 2,8 μg L ). Conclui-se que a "milhocina", suplementada com glicose, é um substrato potencialmente utilizável na preparação de um meio de cultura com um custo substancialmente inferior a um meio que utiliza a triptose.Palavras-chave: controle biológico, processo fermentativo, resíduos agroindustriais.

The well-known entomopathogenic bacterium Bacillus thuringiensis (Bt) produces a spore-crystal complex which is responsible for its biocide characteristic, and the bacterium can be obtained by fermentation, either in liquid or semi-solid substrates. This paper presents a successful way to achieve solid-state fermentation of active Bt var. tolworthi (Btt) against Spodoptera frugiperda (fall armyworm) in corn. More than 10 9 CFU/g were obtained using humidified rice as substrate maintained in polypropylene bags. This active complex (substrate plus spore-crystal of Bt) was prepared in order to obtain 2 x 10 6 spores/mL; the final suspension then sprayed via tractor on corn fields. On the treated plants, mortality of neonate larvae was 100% within two days of spraying, and all larvae were found dead on leaves. During one maize crop cycle, two applications were made, and up until 70 days after emergence it was not necessary to apply any other insecticide for fall armyworm control.

This paper presents a method to estimate the biomass of Spirulina cultivated on solid medium with sugarcane bagasse as a support, in view of the difficulty in determining biomass concentrations in bioprocesses, particularly those conducted in semi-solid or solid media. The genus Spirulina of the family Oscillatoriaceae comprises the group of multicellular filamentous cyanobacteria (blue-green microalgae). Spirulina is used as fish feed in aquaculture, as a food supplement, a source of vitamins, pigments, antioxidants and fatty acids. Therefore, its growth parameters are extremely important in studies of the development and optimization of bioprocesses. For studies of biomass growth, Spirulina platensis was cultured on solid medium using sugarcane bagasse as a support. The biomass thus produced was estimated by determining the protein content of the material grown during the process, based on the ratio of dry weight to protein content obtained in the surface growth experiments. The protein content of the biomass grown in Erlenmeyer flasks on surface medium was examined daily to check the influence of culture time on the protein content of the biomass. The biomass showed an average protein content of 42.2%. This methodology enabled the concentration of biomass adhering to the sugarcane bagasse to be estimated from the indirect measurement of the protein content associated with cell growth.