Study of the cellular retention time and the partial biomass renovation in a fungal decolourisation continuous process

• Published in: Water research (Oxford) Vol. 40; no. 8; pp. 1650 - 1656
• Main Authors: Blánquez, P., Sarrà, M., Vicent, M.T.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2006; Elsevier Science
• Subjects: Applied sciences; Biomass; bioreactors; Color; Coriolus versicolor; decolorization; duration; dyes; enzyme activity; Exact sciences and technology; Fluidised bioreactor; Fungi - cytology; Fungi - metabolism; Laccase; microbial activity; microbial growth; Other industrial wastes. Sewage sludge; pellets; Pollution; simulation models; Textile dye; textile dyes; textile mill effluents; Trametes versicolor; Wastes; wastewater treatment; Water treatment and pollution; white-rot fungi; Textile dye; Trametes versicolor; Laccase; Fluidised bioreactor; Microbial activity; Discoloration; Dyes; Enzyme; Coriolus versicolor; Basidiomycetes; Biomass; Retention time; Long term; Biological purification; Continuous process; Fungi; Bioreactor; Physicochemical purification; Oxidoreductases; Textile industry; Thallophyta
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2006.02.010

The long-term continuous decolourisation treatment of the textile dye Grey Lanaset G (150 mg/l) was carried out in an air-pulsed bed bioreactor with retained pellets of the white-rot fungus Trametes versicolor. Maximum cellular retention time (CRT) was established at 40 days. During this time period, colour reduction remained at 90% and laccase activity was over 400 AU/l. Higher CRTs involved operational problems related to biomass conglomerates formed at the top of the bioreactor, which made individual movement of the pellets difficult. In order to carry out the long-term continuous treatment, a strategy of purge and biomass renovation that had to allow fungal stable activity levels to be maintained was planned. The purge and biomass renovation strategy consists of partial biomass renovations: 1/3 of the total biomass of the system is renewed every 1/3 of the CRT. Different CRTs were tested; with a CRT of 21 days carrying out partial biomass renovations every 7 days and with a hydraulic retention time of 2 days, decolourisation percentages higher than 80% were obtained, maintaining a young culture in the bioreactor and guaranteeing microbial activity. In accordance with the strategy observed, different simulations of the age of the biomass in the bioreactor were carried out, obtaining suitable age distributions for CRT of 20–21 days.