Ana Lúcia Figueiredo Porto

Heavy metal biosorption by chitin and chitosan isolated from Cunninghamella elegans (IFM 46109)

Chitin and chitosan were extracted from mycelial biomass of Cunninghamella elegans and the performance for copper, lead and iron biosorption in aqueous solution was evaluated. The growth curve of C. elegans was accomplished by determination of biomass, pH, glucose and nitrogen consumption. Chitin and chitosan were extracted by alkali-acid treatment and the yields were 23.8 and 7.8%, respectively. For the adsorption analysis, the process of heavy uptake metal sorption was evaluated using polysaccharides solutions (1% w/v). The rate of metallic biosorption was dependent upon the concentration and pH of metal solutions, and the best results were observed with pH 4.0. Chitosan showed the highest affinity for copper and chitin for iron adsorption. The results suggest that C. elegans (IFM 46109) is an attractive source of production of chitin and chitosan, with a great potential of heavy metals bioremediation in polluted environments.

Application of protease from Nocardiopsis sp. as a laundry detergent additive

The application of protease as a laundry detergent additive from a newly isolated Nocardiopsis sp., isolated from a soil sample collected in Northeast Brazil is reported. The optimal pH and temperature for protease activity were pH 10.5 and 50 °C, respectively. The enzyme was stable in a long-term incubation, showed 73.5% of initial activity at pH 10.5 and 61.7% at pH 12.0 for 120 min. Approximately 60% of initial activity remained after 120 min at 50 °C or after 30 min at 80 °C. Almost 87% of enzyme activity was retained in the presence of 10% (v/v) of peroxide at 40 °C, after 1 h. The protease also was stable in the presence of oxidants and surfactants such as SDS, saponin, Tween 20 and Tween 80 after 30 min. In the presence of Omo®, the enzyme retained 64% of its activity at 40 °C for 1 h. An increase in the proteolytic activity (6–17%) was observed with K+, Na+, and Mg++ ions. At pH 8.0, the protease hydrolysed casein maximally (50 U/mg).

Bioemulsifier production in batch culture using glucose as carbon source by Candida lipolytica

The yeast Candida lipolytica IA 1055 produced an inducible extracellular emulsification activity while utilizing glucose at different concentrations as carbon source during batch fermentation at 27°C. In all glucose concentrations studied, maximum production of emulsification activity was detected in the stationary phase of growth, after pH reached minimal values. The bioemulsifier isolated was a complex biopolymer constituting proteins, carbohydrates, and lipids. The results obtained in this work show that the biosynthesis of a bioemulsifier is not simply a prerequisite for the degradation of extracellular hydrocarbon.

Effects of culture conditions on protease production byStreptomyces clavuligerus growing on soy bean flour medium

The influence of nitrogen and phosphate sources on the production of extracellular protease activity byStreptomyces clavuligerus has been investigated. The experiments were carried out in batch fermentation using soy-bean flour as nitrogen source and potassium phosphate dibasic as phosphate source. High protease yield was obtained after 24 h of fermentation with an initial pH of 7.0. The maximal protease activity (112.68 and 88.72 U/mg) was obtained the phosphate concentration of the 21 and 29 mM for strains 3585 and 644, respectively. With regard to the nitrogen concentration in both strains, the maximal protease activity was achieved with 0.5% (154.89 U/mg and 228.36 U/mg for 3585 and 644 strains, respectively). Enzyme production appeared to be modulated by an inducer system where ammonia, complex nitrogen, and phosphate sources might have been involved.

Partition of trypsin in aqueous two-phase systems of poly(ethylene glycol) and cashew-nut tree gum

Abstract The partition behaviour of trypsin in poly(ethylene glycol) (PEG)–cashew-nut tree gum aqueous two-phase systems has been characterized. The enzyme partitioned preferentially into the cashew-nut tree gum phase. Investigation on the effect of the molecular weight of the PEG, the pH of system and the tie-line length of the biphasic diagram lead to the conclusion that the system properties had little effect on trypsin partition coefficients. In some cases, the NaCl addition changed dramatically the partition coefficient, this means that altering the conditions allows the manipulation of the protein partition. Maximum recovery of trypsin activity in the cashew-nut tree gum phase was obtained with PEG (molecular weight 8000) at pH 7.0 and 1.0 M NaCl.

New aqueous two-phase system based on cashew-nut tree gum and poly(ethylene glycol).

The characterisation of a new system based on cashew-nut tree gum, a branched acidic heteropolysaccharide found in Brazil, and poly(ethylene glycol) (PEG) was studied. Phase diagrams are provided for the PEG-cashew-nut tree gum system. The influence of PEG molecular mass, tie-line length and pH on bovine serum albumin (BSA) partition was investigated. Protein partition coefficient was little influenced by changing PEG molecular mass. Increasing the tie-line length decreased the partition. Increasing the pH also raised the BSA partition coefficient. It is shown that systems formed by PEG and cashew-nut tree gum may be considered as an interesting alternative for use in protein purification.

Trichophyton species susceptibility to green and red propolis from Brazil

Aims:  The in vitro antifungal activity of Brazilian green and red propolis was tested against different species of Trichophyton.

Quantification, Antioxidant and Antimicrobial Activity of Phenolics Isolated from Different Extracts of Capsicum frutescens (Pimenta Malagueta)

This paper presents the quantification, antioxidant and antimicrobial activity of capsaicin, dihydrocapsaicin and the flavonoid chrysoeriol isolated from different extracts (hexane and acetonitrile extracts from whole fruit, peel and seed) of Capsicum frutescens (pimenta malagueta). The acetonitrile extract of the seeds, peel and whole fruits contained capsaicin as a major component, followed in abundance by dihydrocapsaicin and chrysoeriol. The antimicrobial activity of the isolated compounds against seven microorganisms showed chrysoeriol was the most active compound. In the antioxidant test, the acetonitrile extract from the whole fruit showed the highest activity. The antioxidant activity of pimenta malagueta may be correlated with its phenolic content, principally with the most active compound, capsaicin.

Extraction of amylase from fermentation broth in poly (Ethylene Glycol) salt aqueous two-phase system

Studies were carried out on the partition of amylase from Bacillus subtilis in a minimal medium at 37 oC and 110 rpm. Enzyme recovery was carried out in aqueous two-phase system PEG-Phosphate salt were carried out. The best purification factor (5.4) was obtained in system PEG 1000 (16.7% w/w) with potassium phosphate (14.8% w/w), at pH 6.0, resulting in a recovery of 45.2% activity enzymatic in the salt-rich phase.

Performance of a perforated rotating disc contactor in the continuous extraction of a protein using the PEG–cashew-nut tree gum aqueous two-phase system

The characterisation of bovine serum albumin (BSA) mass transfer mechanisms in a perforated rotating disc contactor (PRDC) using an aqueous two-phase system (ATPS) composed of poly(ethylene glycol) (PEG) and a polysaccharide, the cashew-nut tree gum, was described. The PEG-rich phase was used as the dispersed phase and protein transfer took place from the dispersed to the continuous phase. Studies of the effect of dispersed phase velocity, system composition and disc rotation speed on either protein mass transfer coefficients or column hold-up showed that the dispersed phase hold-up and the volumetric mass transfer coefficient increased with increasing the dispersed phase velocity and disc rotation speed.