Production of bio-inseticide Bacillus thuringiensis var. israelensis in semicontinuous processes combined with batch processes for sporulation

The aim of this work was to study the production of the bioinsecticide using the aerobic cultivation. Two-stage cultivation process was used: aerobic vegetative growth and end-phase of sporulation (with aeration and without aeration). The cuts of working volume evaluated were 20, 40, 60 and 80 percent. The highest value of spore concentration (2.17x10(9) CFU/mL) and spore productivity (7.2x10(7) CFU/mL.h) were observed using SP60. The lethal concentration (CL50) obtained through the aeration process and non-aeration process were 0.21 and 0.05 mg/L, respectively. The specific potential of the bioinsecticide produced without aeration (0.025 mg/10-12 CFU) was two times higher than that obtained with aeration (0.05 mg/10-12 CFU).

Anaerobic biodegradability of dairy wastewater pretreated with porcine pancreas pipase

Lipids-rich wastewater was partial hydrolyzed with porcine pancreas lipase and the efficiency of the enzymatic pretreatment was verified by the comparative biodegradability tests (crude and treated wastewater). Alternatively, simultaneous run was carried out in which hydrolysis and digestion was performed in the same reactor. Wastewater from dairy industries and low cost lipase preparation at two concentrations (0.05 and 0.5 percent w.v-1) were used. All the samples pretreated with enzyme showed a positive effect on organic matter removal (Chemical Oxygen Demand-COD) and formation of methane. The best results were obtained when hydrolysis and biodegradation were performed simultaneously, attaining high COD and color removal independent of the lipase concentration. The enzymatic treatment considerably improved the anaerobic operational conditions and the effluent quality (lower content of suspended solids and less turbidity). Thus, the use of enzymes such as lipase seemed to be a very promising alternative for treating the wastewaters having high fat and grease contents, such as those from the dairy industry.

O presente trabalho teve como objetivo o pré-tratamento de efluente da indústria de laticínios na hidrólise de lipídeos, empregando lipase de fonte de células animais de baixo custo disponível comercialmente (pâncreas de porco) na formação de gás metano por biodegradabilidade anaeróbia empregando diferentes concentrações de lipase (0,05 e 0,5 por cento w.v-1). A utilização de lipase no pré-tratamento do efluente acelerou a hidrólise de lipídeos e, conseqüentemente, auxiliou o tratamento biológico resultando na redução da matéria orgânica em termos de Demanda Química de Oxigênio (DQO), cor e sólidos em suspensão como lipídeos. Os melhores resultados em termos de remoção de DQO e cor foram obtidos quando a hidrólise e biodigestão foram realizadas simultaneamente, independente da concentração de lipase empregada. Estes resultados mostram que a hidrólise e biodigestão podem ser realizadas simultaneamente empregando baixa concentração de lipase (0,05 por cento w.v-1), contribuindo para a redução de custo e tempo no processo de biodegradação aneróbia.

Viability and infectivity of an ectomycorrhizal inoculum produced in an airlift bioreactor and immobilized in calcium alginate

The viability and infectivity of an ectomycorrhizal inoculum (isolate UFSC-Rh90, Rhizopogon nigrescens), produced by submerged cultivation in an airlift bioreactor and immobilized in beads of calcium alginate gel, was studied. Inoculum remained 100 percent viable after 18 months in a 0.85 percent NaCl solution at 8 ± 1°C. Mycelium grew from the beads after 48 h when they were placed on a solid culture medium at 25 ± 1°C. Viability of pellets of non-immobilized mycelium stored under the same conditions decreased gradually after the third month of storage, reaching 0 percent by the 12th month. These pellets presented a gradual darkening, which was more intense in those located near the surface of the NaCl solution. In culture medium, these dark pellets showed no viability. Gel immobilization helps to maintain mycelium viability during storage and offers a physical protection when the inoculum is applied to the planting substrate. After eight months refrigeration, the immobilized inoculum was still able to infect Pinus taeda seedlings, colonizing an average of 37 percent of the root tips when inoculated in the plant growth substrate under greenhouse conditions. This inoculum presents a commercial potential to be produced and applied in forest nurseries.

Estudou-se a viabilidade e a infectividade de inoculante fúngico ectomicorrízico (isolado UFSC-Rh90, Rhizopogon nigrescens), produzido através de cultivo submerso em biorreator airlift e encapsulado em gel de alginato de cálcio. O inoculante permaneceu viável após 18 meses em solução de NaCl (0,85 por cento) a 8 ± 1°C. O micélio emergiu dessas cápsulas após 48 h de incubação a 25 ± 1°C em meio de cultura sólido. A viabilidade dos pellets de micélio não imobilizado, armazenados sob as mesmas condições, reduziu-se gradualmente após três meses de armazenamento e atingiu 0 por cento aos 12 meses. Esses pellets apresentaram um escurecimento gradual que foi mais intenso naqueles localizados próximos à superfície da solução de NaCl. Em meio de cultura, os pellets escurecidos mostraram-se inviáveis. A imobilização em gel mantém a viabilidade do micélio durante o armazenamento, além de oferecer uma barreira física quando aplicado ao substrato de plantio. Após oito meses de armazenamento sob refrigeração, o inoculante imobilizado colonizou uma média de 37 por cento das raízes curtas de mudas de Pinustaeda, quando aplicado ao substrato de plantio sob condições de casa-de-vegetação. Esse inoculante apresenta potencial para produção comercial e aplicação nos viveiros florestais.