ABSTRACT The combination of 0.5% weight per volume (w/v) crude enzyme consortia produced by solid state fermentation with Penicillium brevicompactum and 27 milligrams per liter (mg/L) of rhamnolipid biosurfactant produced by submerged fermentation with Pseudomonas aeruginosa was employed to pretreat wastewater from a poultry slaughterhouse in bench upflow anaerobic sludge blanket (UASB) bioreactors. One bioreactor was fed with untreated wastewater (Control) and another with pretreated wastewater (Test). Under an organic loading rate of 11 kg COD/m3.d, the Test bioreactor showed higher specific methane production (67.8 mL CH4 (STP)/g COD removed), higher chemical oxygen demand (COD) (91.2%), and oil and grease (O&G) (95.8%) removal than the Control bioreactor, which produced 36.1 - 16.9 mL CH4 (STP)/g COD removed with 72.5% COD removal and 48% O&G removal. The Control bioreactor experienced five clogging episodes due to the accumulation of fat on the surface, while the Test bioreactor operated without operational problems. The scum of the Control bioreactor contained more than 10 times higher quantities of fat than the Test bioreactor. The economic analysis indicated that such alternative technology has lower costs than conventional technology.

Biological production of hydrogen through anaerobic fermentation has received increasing attention and offers a great potential as an alternative process for clean fuel production in the future. Considering biological systems for H2 production, anaerobic fermentation stands out, primarily due to its higher production of H2 compared with other biological processes. In addition the possibility of using different agro-industrial wastes as substrates opens up infinite possibilities. The development and implementation of sustainable processes for converting renewable materials into different value-added products is essential for the full exploitation of Brazilian agro-industrial wastes.