Potencial bioquímico de biogás de resíduo de filetagem de tilápia Oreochromis nilóticos

Abstract

Aquaculture heavily contributes to the good quality protein production and low fat. By the industrialization of tilapia, fillet has been the most commercialized cut. Filleting promotes a use about 35% of the total weight of alive fish, ie about 65% of each fish is waste in the industrial process. Fish residues production can be divided into two groups: a group that has a high commercial value (belly tidbit) and the group that collects unused commercially valuable parts (viscera, head, carcass, fins and skin). With the presence of biodegradable organic matter, these residues can be treated by means of anaerobic digestion that has biogas as one of the main products. The present work has had the objective to verify the biochemical biogas potential of tilapia residue (Oreochromis niloticos). The residue has been fractionated in 7 parts: scale (ESC), mixed (MIX), carcass (CAR), head (CAB), viscera (VIS), skin (PEL) and fin (NAD). The experimental design has been entirely randomized in that each fraction consisted of a treatment with 5 replicates. Biogas production averages have been submitted to variance analysis (ANOVA) and the Tukey test at 95% confidence level. The ESC, MIX, CAR, CAB, VIS, PEL, NAD fractions have had values of 33.69, 34.28, 26.65, 31.02, 42.71, 32.70 and 30.1% ST, respectively. For SV, PEL and VIS have been obtained the highest values , with 99.1 and 97.4%, followed by CAR, MIX, CAB, ESC, NAD, with 86.4, 84.4, 83.4, 71.8 and 69.8%, respectively. There has been a significant difference for the means of biogas production (p <0.05). The highest volumes of accumulated biogas have been obtained for the CAB, CAR and VIS fractions differing statistically from the others, followed by MIX, NAD, PEL and ESC, with 975, 937, 916, 616, 403, 293 LNbiogás kgSV-1 . The CH4 volume per kg of in natura mass (MI) has been in spotlight by VIS fraction as 200 LN CH4 kgMI-1 followed by CAB at 147, MIX at 125, CAR at 119, NAD at 65; PEL at 61 and ESC at 34.22 LNCH4 • kgMI-1. It has been concluded that it is possible to produce biogas by means of tilapia filleting residues. However, it is advisable to remove the scales because this fraction takes a longer period for biodegradation and has the possibility of increasing the residues inside the bio digester besides not having a significant contribution to the production of biogas.