This review provides a summary of the research conducted on the use of crude glycerol, the major byproduct of the biodiesel industry, as substrate for anaerobic co-digestion and production of biogas. In general, for every 100 kg biodiesel produced, approximately 10 kg crude glycerol is generated. Because this glycerol is expensive to purify for use in food, pharmaceutical, or cosmetic industries, biodiesel producers must seek alternative methods for its disposal. Several studies have demonstrated that the use of crude glycerol as a C source for fermentation and biogas generation is a promising alternative use for this waste material. The high C content of glycerol increases the C:N ratio in the mixture, avoiding the inhibition of the process by the excess of N increasing methane production of digesters by 50 to 200%. Anaerobic codigestion of glycerol and a variety of residual biomasses may be a good integrated solution for managing these wastes and simultaneously producing a source of bioenergy in an environmentally friendly way. On the other hand, after anaerobic treatment of glycerol, an organic matter-rich solid waste is generated (digestate). The incorporation of digestates from glycerol co-digestion to soils constitutes an important source of organic matter and nutrients for plants. However, the potential of digestates as an organic soil amendment has not been sufficiently studied. The utilization of glycerol as a potential source of energy, rather than as a waste, seems to be a convenient way of lowering the costs of biodiesel production and making this emerging industry more competitive.

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ResumenSe estudió el potencial de distintos residuos forestales como sustrato para el cultivo del hongo Pleurotus ostreatus. Para ello, se analizó la composición química de estos residuos, antes y después de la etapa de cosecha, y se midieron distintas variables fenológicas y morfológicas así como el rendimiento y la calidad de los cuerpos fructíferos de Pleurotus ostreatus tras la cosecha. Se fijaron cuatro tratamientos: astillas de álamo, astillas de eucalipto, mezcla de paja de trigo y eucalipto, y paja de trigo como testigo. Los resultados obtenidos indicaron que todos los sustratos, principalmente paja de trigo y mezcla paja de trigo más eucalipto son aptos para el cultivo de Pleurotus ostreatus. El nivel proteico de este hongo fue elevado en todos los sustratos y la relación carbono/nitrógeno de los mismos disminuyó después de cosecha. Palabras clave: hongo ostra, residuos forestales, residuos lignocelulósicos, sustratos Use of Lignocellulosic Forest Residues for Oyster Mushroom Production (Pleurotus ostreatus) AbstractOrganic waste resulting from the forest practices, containing lignocellulosic carbon sources, was used in the production of the mushroom specie Pleurotus ostreatus. For this, the chemical composition before and after harvest were analyzed, the phenological and morphological variables were determined and yield and quality of harvested fruit bodies also determined. Four treatments were performed: chips of poplars, chips of eucalyptus, a mixture of wheat straw and eucalyptus, and wheat straw as witness. The results showed that all substrates, especially wheat straw and wheat straw with eucalyptus, are suitable for the production of Pleurotus ostreatus. This species showed a high protein level in all the studied substrates, and the ratio carbon/nitrogen decreased after harvest.

ResumenSe resume y analiza algunas tecnologías que se han implementado para la purificación de biogás usado en la generación eléctrica. Se sabe que el biogás puede contener algunas impurezas y elementos traza que deben ser removidas antes de su uso en la matriz energética. Las tecnologías tradicionales para la purificación de biogás están basadas fundamentalmente en el empleo de métodos físicos y químicos, los cuales, además de generar contaminantes secundarios, a menudo tienen un alto costo. Como una alternativa, la purificación de biogás mediante procesos biológicos utilizando microorganismos parece atractiva. Los microorganismos pueden remover las sustancias consideradas contaminantes, especialmente para la eliminación de sulfuro de hidrógeno. Ser concluye que se trata de un método económico, con bajos gastos energéticos e inocuo para el medio ambiente y la salud humana. AbstractAvailable technologies that have been implemented for biogas purification for its use in power generation are summarized and analyzed. It is known that biogas may contain some impurities and trace elements that must be removed before its use as energy source. Traditional technologies for biogas purification are based primarily on the use of physical and chemical methods, which, besides generating secondary pollutants, often have a high cost. As an alternative, biogas purification through biological processes using microorganisms has become attractive. The microorganisms can remove substances considered pollutants; especially they can remove hydrogen sulfide. It is concluded that the method is cost effective with low energy inputs and harmless to the environment and human health.

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