ESTUDO DA BIODEGRADAÇÃO DO FENOL POR UMA NOVA LINHAGEM DE Aspergillus sp.
The presence of chemical industrial installations in Rio Grande ? RS, near to a complex ecosystem, that include Patos Lagoon estuary, has a serious environmental impact, with damage in economic activities such as fishery and tourism. In this context, research and development strategies to impacted areas recovery are essential. Bioaugmentation involves the addition of an expressive number of hydrocarbonclastic microorganisms in impacted areas. It is interesting the application of selected microorganisms from indigenous population, adapted to local conditions and with high degradation capacity. Phenols, in particular, are hazardous pollutants, because of antimicrobial and phytotoxic effects. The main goal of this work was to study the phenol degradation capacity of Aspergillus sp. LEBM2 filamentous fungus, isolated by Microbiology Laboratory ? FURG, in the region of Rio Grande - RS. Different types of innoculum were studied, using different carbon sources. Influence of batch cultivation parameters (glucose concentration, innoculum volume and agitation) was verified using a 2³ experimental design. Phenol tolerance was studied, verifying degradative capacity for different contaminant concentrations. A comparative study was carried out with free and encapsulated microorganisms. With respect to the type of innoculum, it was observed significative differences. A more efficient process was obtained using an adaptation medium containing glucose and phenol, reaching a degradation rate of 0.67 mg.L-1.h-1. In relation to experimental design, glucose concentration of 500 mg.L-1, innoculum volume of 20 % and agitation of 200 rpm were the best conditions, with total phenol degradation in 72 h and degradation rate of 3.76 mg.L-1.h-1. With respect to phenol tolerance, this microorganism was able to consume 989 ± 15 mg.L-1. The highest phenol degradation rate was 5.18 mg.L-1 in the concentration of 320 ± 0,57 mg.L-1, showing that Aspergillus sp. LEBM2 has great potential to bioaugmentation purposes. In the comparative study involving free and encapsulated cells, it was observed an increase in phenol degradation rate with filamentous fungi encapsulated in calcium alginate beads, in all concentrations. The presence of a microenvironment more favorable, because of the protector effect of gel matrix, reduced abiotic stress. Encapsulated Aspergillus sp. LEBM2 application showed a potential technique for bioaugmentation processes.
Advisor:Carlos André Veiga Burkert; Susana Juliano Kalil; Marcelo Hemkemeier; Luiz Antonio de Almeida Pinto
School:Fundação Universidade Federal do Rio Grande
Source Type:Master's Thesis
Date of Publication:03/13/2006