Feedstock enzymatic pre-treatment for improvement of biogas production

08/08/2019

Summary

This technology allows an improvement in the efficiency of the biogas production process through the pre-treatment of feedstock with a cocktail of cellulolytic and hemicellulolytic enzymes.

Technology Description

The biogas production process has a limited efficiency due to the poor conversion of cellulose and hemicellulose into biogas by the anaerobic methanogenic consortia. Pre-treatment of feedstock with a cocktail of cellulolytic and hemicellulolytic enzymes should improve the efficiency of the process. Researchers have used an intense mathematical model-based screen to identify fungal isolates whose secretome can degrade biomass more efficiently than commercial cellulase formulations. Several enzymes have been characterized and among them, a specific one, was found to be the most important cellulolytic enzyme for crystalline cellulose breakdown. This enzyme deriving from a new fungal isolate, Penicillium funicolosum, exhibited a high catalytic efficiency as well as a high enzyme-inhibitor complex equilibrium dissociation constant (Ki). Moreover, an E. coli-based heterologous expression system was used to produce cellulases (glycosylhydrolase or endoglucanase) to add in the enzymatic cocktail. Indeed, this enzyme has been proved to be able to release simple sugars from raw materials such as microcristalline cellulose, corn cob powder and corn stalk powder. In conclusion, researchers propose to use this enzymatic cocktail for the improvement of biogas production in industrial biogas digestors.

Main advantages

The proposed technology has the advantage of using highly efficient heterologously expressed enzymes or engineered fungal enzyme cocktails that are supposed to have better performances than the products already in the market, since these last ones are obtained by simple cultivation of cellulolytic fungi and recovery of the culture supernatant. The technology seems to be suitable for being used also in the pre-treatment of feedstock used in biogas digestors.

Stage of development

Penicillium funicolosum has been genetically modified and made able to produce high amount of cellulolytic and hemicellulolytic enzymes. The resulting fungus showed excellent production of stable and efficient hydrolytic enzymes. The enzymatic cocktail obtained was tested on several substrates and raw materials and resulted more efficient than other products currently on the market, being therefore suitable for pre-treatment of biomasses in biogas digestor processes. The potential of improving the BMP (Biological Methane Potential) must be tested. In conclusion, researchers have proved that the results are positive at laboratory level, but they need to be confirmed at industrial level.

Challenge and needs

Biogas is a mixture of different gases produced by anaerobic fermentation of wastes and other biodegradable materials. It can be produced from diverse organic materials such as food waste, sewage sludge, agricultural wastes, industrial wastes (especially industrial food waste), animal by-products and municipal solid wastes using various methods. Biogas is produced in a biogas digester where the bacteria and fungi need to be properly cared. Biogas is composed of approximately 50% to 65% methane, plus carbon dioxide and various trace gases. This technology wants to tackle on the

improvement of the efficiency of biogas production in anaerobic digestors through the use of genetic engineering and molecular biology. It is known that some components of the feedstock, such as cellulose and hemicellulose, are poorly converted into biogas. This is proved by the presence of abundant residual cellulose and hemicellulose in the digestate. Therefore, the proposed application of the technology (enzymes cocktail) is the following:

  1. pre-treatment of feedstock before the biogas digestion process for enrichment of simple sugars and polysaccharides;
  2. the enzymatic treatment of digestate (process residue) for releasing simple sugars obtained by hydrolysis of residue polysaccharides, followed by recycling into the digestor. 

Intellectual property

The technology is not yet protected by a patent by a patent.

Potential markets and targets

The waste-derived biogas market already exists but it offers few and not satisfactory performing products. Hence, the market is potentially huge. Global markets increased from $5.6 billion in 2016 to $6.1 billion in 2017, and will further advance to $10.1 billion by 2022, for a 2017 to 2022 compound annual growth rate (CAGR) of 10.6%. Thus, any product that could improve of only 5% the production of biogas could generate a significant business. The global market for biogas, in terms of volume, stood at 354 KT in 2015; this is projected to reach 450 KT by 2022, at a CAGR of 3,5%.

Potential partners

The potential partner should know very well the technology of biogas production, the management of the process, the related problems connected with the technology and, in addition, should have contacts with biogas producers as well as the Consortia that assist and regulate this industrial field. The ideal partner should also be able to evaluate the technology from an economic point of view.   

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