Fungal biodegradation of plantain peel for broiler finisher feeding: In vitro digestibility, effects on performance, haematological and serum parameters

The objective of this study was to investigate the changes in in-vitro dry matter digestibility (IVDMD) of plantain peel (PPL) after its biodegradation with Aspergillus niger and also to determine the effect of degraded PPL on the performance, nutrient digestibility, weights of internal organs, haematological and serum biochemical parameters of broiler finishers. A total of 165 uns exed broiler finishers that were 4 weeks old were used. Aspergillus niger was used for the biodegradation of PPL. There were five dietary treatments of 33 birds each. There were 0 % inclusion level of PPL (control), 7% inclusion level of undegraded PPL (UPPL) then 3, 5 and 7% inclusion levels of degraded PPL (DPPL). Completely Randomized Design (CRD) was adopted. Weight gain was significantly (P<0.05) higher with the birds fed degraded PPL. The highest value (46.39 gramin /bird) was found in treatment 5 (7% DPPL) and the lowest value (38.05 gramme /bird) was found in treatment 2 (7% UPPL). Feed conversion ratio (P<0.05) was best (2.22) in birds placed on 7% DPPL and this is comparable to those on 0%PPL, 3%D PPL and 5%DPPL. There were significant (P<0.05) differences in the digestibility of dry matter, crude protein and crude fibre. Crop, gizzard and abdominal fat were significantly (P<0.05) affected. The values of packed cell volume (PCW), mean corpuscular volume ( MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) total protein, cholesterol and glucose were significantly (P<0.05) affected by the treatments. Fungal biodegradation of PPL using A.niger has the potential of enhancing feed intake, nutrient digestibility and the body weight gain of broiler finisher. Key words: ,, .

Biodegradation of Atrazine and Ligninolytic Enzyme Production by Basidiomycete Strains

Atrazine is one of the most widespread chlorinated herbicides, leaving large bulks in soils and groundwater. The metabolic pathways of biodegradation of atrazine by bacteria are well described, but many aspects of the fungal biodegradation of this compound remain unclear. Thus, we investigated the toxicity and degradation of atrazine by 13 rainforest basidiomycete strains. In liquid medium, Pluteus cubensis SXS320, Gloelophyllum striatum MCA7, and Agaricales MCA17 removed 30, 37, and 38%, respectively, of initial 25 mg L -1 of herbicide within 20 days. Deficiency of nitrogen drove atrazine degradation by Pluteus cubensis SXS320; this strain removed 30% of atrazine within 20 days in a culture medium with 2.5mM of N, raising three metabolites; in a medium with 25mM of N, only 21% of initial atrazine were removed after 40 days, and two metabolites appeared in culture extracts. This is the first report of such different outcomes linked to nitrogen availability during the biodegradation of atrazine by basidiomycetes. The herbicide also induced synthesis and secretion of extracellular laccases by Datronia caperata MCA5, Pycnoporus sanguineus MCA16, and Polyporus tenuiculus MCA11. Laccase levels in contaminated medium of P. tenuiculus MCA11 were 13.3-fold superior than in control; the possible role on this enzyme on atrazine biodegradation was evaluated, considering the strong induction and the removal of 13.9% of the herbicide in vivo . Although 88% of initial laccase activity remained after 6h, no evidence of in vitro degradation was observed, even though ABTS was present as mediator. Further studies, including a full characterization of the metabolites obtained, are desirable to assess the security of the use of these strains as in situ bioremediation tools. The search for other ligninolytic extracellular enzymes and cell-bound mechanisms implicated on the degradation would enlightens key aspects of the role of nitrogen in atrazine metabolism by basidiomycetes.

Bioremediation of soils contaminated with petroleum solid wastes and drill cuttings byPleurotussp. strains under different treatment scales

Wastes from the oil industry represent one of the sources of soil pollution with the greatest environmental impact. Both drill cuttings and crude residues are delivered to the soil and produce severe toxic effects, mainly due to the presence of polycyclic aromatic hydrocarbons. Various bioremediation technologies have been implemented in order to restore the soil quality and the natural auto depuration capabilities, amongst them: composting, bioaugmentation and biostimulation. All of these bioremediation techniques promise to be eco-friendlier and cheaper alternatives than other approaches. In this work we have evaluated several strains ofPleurotussp. for their effect on the bioremediation of oil-contaminated wastes and drill cuttings disposed in storage tanks or in open-air soil lots for many years. Our results suggest that combined natural attenuation mechanism and directed fungal biodegradation activities, could be promising strategies to remediate heavily petroleum polluted soils and drilling wastes both at the laboratory and in field conditions. Furthermore, we present new data that supportingPleurotusgenera as able to degrade asphaltenes, the most recalcitrant fraction of petroleum. This study proposes an approach that at the same time can treat soils contaminated with waste from drill cuttings and bottoms of crude storage tanks.