Molecular characterisation and biomass and metabolite production of Lactobacillus reuteri LPB P01-001: a potential probiotic

Lactobacillus reuteri LPB P01-001 was isolated from the gastrointestinal tract of wild swine and was characterised by biochemical testing and sequencing of gene 16S rRNA. A simple and low-cost culture medium based on cane sugar (2.5% p/v) and yeast extract (1% p/v) was used in the production of this probiotic. The fermentative conditions were a) pH control at 6.5 and b) no pH control; both were set at 37°C in a 12 L slightly stirred tank bioreactor. Fermentation parameters such as the specific growth rate, productivity and yield of biomass, lactic and acetic acid levels were determined. L. reuteri LPB P01-001 behaves as an aciduric bacteria because it grows better in a low pH medium without pH control. However, the lactic acid production yield was practically half (9.22 g.L-1) of that obtained under a constant pH of 6.5, which reached 30.5 g.L-1 after 28 hours of fermentation. The acetic acid production was also higher under pH-controlled fermentation, reaching 10.09 g.L-1 after 28 hours of fermentation. These parameters may raise the interest of those committed to the efficient production of a probiotic agent for swine.

Evaluation of Bacillus sphaericus bioinsecticide produced with white soybean meal as culture medium for the control of Culex (Culex) quinquefasciatus / Avaliação do bioinseticida de Bacillus sphaericus, produzido com meio de cultivo de farelo branco de soja no controle de Culex (Culex) quinquefasciatus

Bioinsecticides are shown to be useful in control programs to prevent several diseases, based on their specificity and efficiency against insect vectors. In the current study a bioinsecticide based on Bacillus sphaericus was produced using a white soybean culture medium and applied to larvae of Culex quinquefasciatus, the susceptible species, and Aedes aegypti, the refractory species used as the negative control. Efficacy was compared with that of the product fermented with the Luria Bertani (LB) reference medium. The experiments showed that C. quinquefasciatus was highly susceptible to the product prepared with white soybean meal, reaching 100 percent larval mortality even at 10mg/L, while A. aegypti failed to reach 70 percent mortality at a concentration of 1g/L. By comparison with the reference medium, the proposed culture medium showed high larvicidal power, reaching a LD90 of 2.26mg/L, while 4.37mg/L was needed for the LB medium to achieve the same mortality rate. Cost comparison between the formulations favored the use of the bioinsecticide produced with white soybean meal. After factoring in the LD90 value, the cost ratio favored the new raw material by nearly 1:220.

A utilização de bioinseticidas tem se mostrado útil aos programas de prevenção de diversas enfermidades devido a sua especificidade e eficiência contra insetos vetores. No presente trabalho, o bioinseticida de Bacillus sphaericus foi produzido com um meio de cultivo composto de farelo branco de soja e aplicado em larvas de Culex quinquefasciatus, espécie susce-tível, e Aedes aegypti, espécie refratária, usada como controle negativo. O desempenho foi comparado com o do produto fermentado com o meio referência Luria Bertani (LB). Os experimentos constataram que C. quinquefasciatus apresentou uma alta suscetibilidade ao produto produzido com farelo branco de soja, alcançando mortalidade de 100 por cento mesmo na diluição de 10mg/L, enquanto A. aegypti não atingiu 70 por cento na concentração de 1g/L. Quando comparado com o meio referência, a formulação proposta proporcionou um alto poder larvicida, alcançando uma DL90 de 2,26mg/L, ao passo que LB precisou de 4,37mg/L para a mesma mortalidade. A comparação do custo das formulações favoreceu o bioinseticida produzido com o meio farelo branco de soja. Considerando os valores de DL90, a relação do custo das matérias-primas ficou próxima de 1:220.

Physiological changes of Candida tropicalis population degrading phenol in fed batch reactor

Candida tropicalis can use phenol as the sole carbon and energy source. Experiments regarding phenol degradations from the water phase were carried out. The fermentor was operated as a fed-batch system with oxistat control. Under conditions of nutrient limitation and an excess of oxygen the respiration activity of cells was suppressed and some color metabolites (black-brown) started to be formed. An accumulation of these products inhibited the cell growth under aerobic conditions. Another impact was a decrease of the phenol hydroxylase activity as the key enzyme of the phenol degradation pathway at the end of the cell respiration activity. This decrease is linked with the above mentioned product inhibition. The cell death studied by fluorescent probe proceeded very slowly after the loss of the respiration activity. The starvation stress induced an increase of the endogenous respiration rate at the expense of phenol oxidation

Bioremediation: an important alternative for soil and industrial wastes clean-up.

Industrial and environmental biotechnology are going to new paths, resulting in processes with "clean technologies", with the maximum production and the less residues. Technologies of remediation and bioremediation are continuously being improved using genetically modified microorganisms or those naturally occurring, to clean residues and contaminated areas from toxic organics. Bioremediation of soils, water and marine environments has many advantages but at the same time it is a challenge for the researchers and engineers. Consequently, it is extremely important to carry out feasibility study based on pilot-testing before starting a remediation project in order to determine the best conditions for the process. The article presents a brief review of bioremediation including the description of the different methods applied to soil and industrial wastes, and, finally, some experiences of solid-state fermentation in relation to bioremediation.

Isolation, identification and physiological study of Lactobacillus fermentum LPB for use as probiotic in chickens

Studies were carried out to isolate and identify microorganisms for probiotic use for chickens. Selection of strains included various criteria such as agreement with bio-safety aspects, viability during storage, tolerance to low pH/ gastric juice, bile, and antimicrobial activity. The strains were isolated from the crop, proventriculus, gizzard, ileum and caeca of chicken. Decimal dilution of the contents of these segments were mixed with MRS medium and incubated for 48 h at 37ºC under anaerobiosis. The identity of the culture was based on characteristics of lactobacilli as presented in the Bergey's Manual of Determinative Bacteriology, carrying out bacterioscopy (morphology), Gram stain, growth at 15 and 45ºC, and fermentation of different carbon sources. Based on these criteria, Lactobacillus fermentum LPB was identified and tested for probiotic use for chickens. The isolate was evaluated for poultry feeds supplement. The results showed that in comparison to the presence and effects of antibiotics, L. fermentum LPB implantation resulted in a similar effects as that of antibiotics manifested by feed efficiency in growth of chicks.

Microbial production of citric acid

O ácido cítrico é o ácido mais produzido em termos de tonagem e é extensivamente utilizado pelas indústrias alimentícia e farmacêutica. É produzido principalmente por fermentaçäo submersa utilizando o fungo Aspergillus niger e leveduras do gênero Candida sp. à partir de diferentes forntes de carbono, como a glicose e meios à base de amido. No entanto, outras técnicas de fermentaçäo, e.g. fermentaçäo no estado sólido e em superfície, e fontes alternativas de carbono tem sido intensamente estudadas mostrando grande perspectivas para o processo. O presente trabalho apresenta um resumo dos últimos avanços sobre a produçäo do ácido cítrico, descrevendo de maneira sucinta os trabalhos mais recentes, descrevendo microorganismos, técnicas de produçäo e substratos empregados, etc

Fruity aroma production by Ceratocystis fimbriata in solid cultures from agro-industrial wastes

Solid state fermentations were carried out to test the efficacy of Ceratocystis fimbriata to grow on different agro-industrial substrates and aroma production. Seven media were prepared using cassava bagasse, apple pomace, amaranth and soya bean. All the media supported fungal growth. While amaranth medium produced pineapple aroma, media containing cassava bagasse, apple pomace and soya bean produced a strong fruity aroma. The aroma production was growth dependent and the maximum aroma intensity was detected a few hours before or after the maximun respirometric activity. Sixteen compounds were separated by gas cromatography of the components present in the headspace and fifteen of them were identified as acid (l), alcohols (6), aldehyde (l), ketones (2) and esters (5).

Bioconversion of biomass: a case study of ligno-cellulosics, bioconversion in solid state fermentation

Lignocellulosic residues obtained from crops cultivation form usefulsources to be used as substrate for bioconversion processes. Sugarcane bagasse, which is a complex substrate obtained from the processing of sugarcane, is an important biomass among such sources. Due to its abundant avaiability, it can serve as an ideal substrate for microbial processes for the production of value added products. This paper reviews recent developments an biological processes developed an production of various products in solid state fermentation using sugarcane bagasse as the subastrate and describes production of protein enriched feed, enzymes, amino acid, organic acids and compounds of pharmaceutical importance, etc. through microbial means