Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)

Supplementation of mushroom substrates has been linked to a higher resistance against insect pests, although few studies show the impact of this supplementation on the different agronomical parameters of mushrooms or even their chemical composition. In this work, the variation in the biological and chemical composition of oyster mushroom (Pleurotus ostreatus var. florida (Jacq.) P. Kumm) was analysed after varying the substrate supplementation of calcium silicate (0, 0.5, 1, 2, and 4% (w/w%)) during two harvest flushes. Overall, supplementation did not change the weight, the number of fruiting bodies, biological efficiency, yield ratio, and productivity rate of the mushrooms, although the harvest flushes did show significant differences. Furthermore, slight changes were found in the chemical composition with an increase in vitamin D2 and tocopherols for the mushrooms with higher amounts of calcium silicate. Overall, the substrate supplementation did not seem to induce expressive changes or decrease production yields, and can, therefore, continue to be researched as a potential application to fight agronomical pests.

Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)

The aim of this research was to evaluate the efficiency of aqueous alkali-treated Brachiaria straw for the cultivation of appropriate species of oyster mushroom. The substrate used in the cultivation of various Pleurotus spp. was soaked for 20min by using two different procedures: (i) 0.5-2.0% Ca(OH) in 100L water, and (ii) 50-250L water. As a result, 1% Ca(OH) dissolved in 100L water and 3.5kg of Brachiaria straw presented the best production. The most suitable species for the application of the present method were P. pulmonarius and P. sapidus. The success of this technique is directly related to the concentration of Ca(OH) and water, the species, and the origin and quality of raw material used as the substrate in the production of oyster mushroom.

The productivity parameters of 2 Pleurotus spp. cultivated with two mixtures of wheat straw (WS) and peat moss (MG) were evaluated, the chemical composition of the mushrooms and also the antioxidant, antibacterial activities of hexanic extracts of the fruit bodies were determined. Pleurotus strains were fructified using the mixture 1 (60% of WS + 40% of MG) obtained the highest biological efficiencies, production rates and yields. The strain of Pleurotus ostreatus (XC005) cultivated using the mixture 2 (80% WS + 20% of MG) presented fruit bodies with highest protein content being of 25.28%, and also the strain of Pleurotus djamor (XC007) fructified on the mixture 2 showed mushrooms with highest protein content being of 30.98%. The highest antioxidant effect resulted in the hexanic extract of the Pleurotus ostreatus cultivated on M2 was found using the TBARS inhibition assay (EC50 = 0.12 mg mL- 1), while the highest antioxidant activity showed the hexanic extract of the Pleurotus djamor produced on M1 was found using the TBARS inhibition assay (EC50 = 0.21 mg mL- 1). The bactericidal effect of the hexanic extracts of Pleurotus ostreatus was obtained between 21.09 to 27.90 mg mL−1, whereas the bacteriostatic activity of the hexanic extracts of Pleurotus djamor was achieved since 19.82 to 30.98 mg mL−1. The results evidenced that the Pleurotus spp. cultivated on the mixture 2 presented highest protein content and better biological properties, encouraging the production of edible fungi strains and their use in the industrial field.