Burgos, R1, Nascimento, A. E2, Lima, M. A. B.3* 1,2
Universidade católica de Pernambuco – UNICAP,Rua do Príncipe, 526 - Boa Vista, 50050-900 Recife- PE. 3
Table 1. Growth profile of Aspergillus nidulans in media tested
Universidade Federal Rural de Pernambuco – UFRPE, Rua Dom Manoel de Medeiros S/N - Dois Irmãos, 52171-900 - Recife, PE. *mabl@bol.com.br
Key Words; phenoloxidases, cadmium, Aspergillus nidulans
INTRODUCTION: Heavy metal accumulation in agricultural soils is an aspect of serious concern related to environmental security, because those substances can express its pollution potential on soil organisms, on plants in phytotoxic levels, as well as by the transference to trophic chains through plants or by waters contamination (MARIA, L.S.S. et al., 2007). The correlation between enzymatic activity and the survival ability in presence of heavy metal in the environment its suggested (LLOYD, J.R., 2002). The aim of this work was evaluate the Aspergillus nidulans growth and the activity of tannase, phenoloxidase and amylase in medium containing cadmium in concentrations of 1mM, 2mM and 3mM.
MATERIAL E METHODS: The analysis of enzymatic activity was evaluated in culture medium containing different substrata. Galic acid, tanic acid and soluble starch were used for phenoloxidase, tannase and amylase, respectively. The fungus was growth during 5 days, at 28°C. The radial colony growth and the enzymes activities were observed each 24h.
RESULTS AND DISCUSSION: The results obtained for the fungus growth in the different media tested are presented in Table 1.
TANASE PHENOLOXIDASE AMYLASE
24h 48h 72h 96h 120h 24h 48h 72h 96h 120h 24h 48h 72h 96h 120h Control 1,4 2,8 5,1 7 9 2 5,8 7,9 9 9 1,5 3 4,45 5,05 5,6
1mM 0 0 0 0 0 1,1 3,3 3,9 4,5 5,3 0,6 1,2 1,75 1,9 2,45
2mM 0 0 0 0 0 0,7 2,2 2,6 3 3 0,5 1 1,45 1,75 2,05
3mM 0 0 0 0 0 0,6 1,8 1,9 1,9 1,9 0 0 0 0 0
It is possible to observe that the isolate exhibited a higher growth in control media, and the radial colony ramification was related to cadmium concentration used in culture media. For tanase medium the fungus grew only in control condition, but exhibited enzymatic activity in all media containing cadmium (figure 1-B), When tested in media for amylase the fungus exhibited a exuberant growth and the activity was detected in all conditions tested (figura 1-C). A similar response was noted for phenoloxidase experiments (figura 1-A). Those results are the first related to cadmium presence.
CONCLUSIONS: The fungus exhibited a positive response for the enzymes tested. In cadmium presence the tanase activity was noted but the growth was inhibited; in medium for phenoloxidase activity, the cellular growth and enzyme activity were the highest; In medium for amylase activity the growth and the enzyme were inhibited only in presence of 3mM of cadmium.
REFERENCES:
LLOYD, J.R. Bioremediation of metals; the application of micro-organisms that make and break minerals. Microbiology Today., 29: 235-256, 2002.
MARIA, L.S.S.; GODOFREDO, C.V.; ANDERSON, R.T. Concentração de metais pesados em grãos de plantas cultivadas em solo com diferentes níveis de contaminação. Pesquisa Agropecuaria Brasileira, 42: 2007.
Financial Support:CNPq
Figure 1. Colonies growrth of Aspergillus nidulans in media for enzymatic indicators. A. Phenoloxidase; B. Tanase; C. Amylase
THE USE OF LOW-COST RAW MATERIAL TO BIOPOLYMER PRODUCTION
Oliveira, J. D.1*, Sérvulo, E. F. C.2, Pimenta, F. D.3, Lopes, L. M. A4.1,2Laboratório de Microbiologia Industrial, Escola de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil; 3Centro de Tecnologia da Indústria Química e Têxtil, Senai/Cetiqt, Rio de Janeiro, RJ, Brasil; 4Instituto de Macromoléculas, Universidade Federal do
Rio de Janeiro, Rio de Janeiro, RJ, Brasil * davies.juliana@gmail.com Keywords: pullulan; biopolymer; industrial residual
INTRODUCTION: Microbial biopolymers are polysaccharides produced by microorganisms whose rheologic properties allow for additional applications in various industrial sectors. Among biopolymers, pullulan, a linear neutral homopolysaccharide mainly produced by the dimorphic fungus Aureobasidium pullulans under aerobic conditions, stands out. Pullulan’s physicochemical properties enable its use not only in the food, cosmetic, and pharmaceutical industries, but also for more noble purposes, as for combined vaccine and interferon. This study aimed to evaluate the effect of five nitrogen sources in different concentrations and of two strains of A. pullulans, to reduce costs and maximize the process yield.
MATERIAL AND METHODS: The experiments were performed in batch reactors using basic mineral medium consisting of 30 g/L of crystal sugar and the nitrogen sources – ammonium sulfate, sodium nitrate, ammonium nitrate, urea, and residual brewery yeast – in order to establish a carbon/nitrogen (C/N) ratio of 5, and 150. After 48 hours of incubation in 28 ± 1°C, under agitation of 150 rpm, the following determinations were performed: cellular concentration, substrate consumption, polymer yield, pH, and viscosity.
RESULTS AND DISCUSSION: All nitrogen sources, in the proportions tested, were capable of fostering cell growth and biopolymer production by both strains. However, both the amount of gum produced and the fermented broth viscosity were dependent on microbial strain, the nitrogen source, and the C/N ratio. Overall, the best results for the different conditions were observed for the IOC 3011 strain. Among the nitrogen sources, the residual brewery yeast (LRC) fostered the greatest yieldof biopolymer. The LRC was even better than the ammonium sulfate, which is the nitrogen source usually recommended to obtain this biopolymer. The brewery residue used also fostered the generation of fermented broth with high viscosity values – 0.06 Pa.s 0.008 Pa.s, respectively in the lowest (15.6 s-1) and the highest (415 s-1) shear rate.
CONCLUSION: The use of residual brewery yeast was the source of nitrogen that obtained higher values of viscosity and yield.
REFERENCES:
BARBOSA, A. M.. CUNHA, P. D.; MAGRINI, M., CORRADI DA SILVA, M.L.C. Produção e aplicações de exopolissacarídeos fúngicos. Semina: Ciências Exatas e Tecnológicas, Londrina, v. 25, n. 1, p. 29-42, jan./jun. 2004.
BOBBIO, F. O., BOBBIO, P. A. Introdução à Química de Alimento. 2ª ed., Livraria Varela: São Paulo, 1992.–209. 1999.
KACHHAWA; D. K.; BHATTACHARJEE, P.; SINGHAL, R. S. Studies on downstream processing of pullulan. Carbohydrate Polymers, v. 52, p. 25-28. 2003.