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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - DEMETER (Demonstrating more efficient enzyme production to increase biogas yields)

Teaser

Nowadays, the transition from an economy dependent upon fossil resources to a sustainable bio-based economy is becoming a priority for the society. One of the most promising developments in this regard is the conversion of biomass into energy sources (biofuels, biogas), making...

Summary

Nowadays, the transition from an economy dependent upon fossil resources to a sustainable bio-based economy is becoming a priority for the society. One of the most promising developments in this regard is the conversion of biomass into energy sources (biofuels, biogas), making the optimization of these conversion strategies an essential step to reach such transition. For the efficient conversion of biomass or agricultural, industrial and municipal waste into fermentable sugars, chemical building blocks or bio-based materials, enzymes play an indispensable role. However, enzymes have not been specifically developed for the biogas production so far. Recently, GIBV has developed a new enzyme product derived from the fungus Myceliophthora thermophila C1, that has proven to have the potential to increase biogas production by at least 10%. Although the efficacy of the enzyme has clearly been shown, the current fermentation process does not provide sufficient yield in industrial production to be cost-effective for large-scale application.

DEMETER will bring innovation to both the fermentation process used for production of the enzyme, and to the use of enzyme-enhanced fermentation in production of biogas. It aims to optimize the fermentation process of the C1 product and demonstrate this on industrial scale. The objective of DEMETER is to increase the yield of this industrial fermentation process by at least 20%, improve the product recovery process by 40%, and reduce overall product costs by at least 15% while increasing the productivity of the process. In addition, DEMETER will demonstrate the efficiency of the enzyme in seven or eight field trials in biogas plants throughout Europe.

Work performed

During the first 18 months of the DEMETER activities, many progress and results have been achieved. An improved fermentation process for enzyme production at lab-scale was developed by GIBV and transferred to partner BBEPP for scale-up to pilot level and first runs at industrial scale. The results have also been used to develop a mathematical model based on all the different variables and parameters present in the fermentation process. The model has recently been finalized and will now be used to improve fermentation protocol further to get a more efficient enzyme production process. The improved fermentation process has been successfully transferred to BBEPP and showed an improved yield in 1500L scale fermenters: 35% more protein has been produced. BBEPP has also compared different strategies to optimize the downstream process for enzymes purification. Scale-up to 1500L has been performed and the recovery has been improved to >90%.

DBFZ has performed laboratory tests in batch and semi-continuous scale for wet biogas fermentation processes. All together eight semi-continuous biogas tests with a substrate mixture of straw plus cow manure and rye-silage plus cow manure are now still in operation. So far the effect of the enzyme addition is very limited, which might be due to the optimized process conditions in the lab scale fermenters. A second set of semi-continuous biogas tests will be performed in which the process conditions will be less optimized. A dry biogas process has been tested at laboratory scale by OWS in batch and continuous digesters to assess the long-term effect of the enzyme on different types of organic waste materials. For each substrate, 4 reactors were start-up: 2 without enzyme and 2 with enzyme addition. So far, a small effect of the enzyme has been observed in the mesophilic agricultural digesters (2% more biogas produced and a higher process stability) and in the thermophilic OF-MSW digesters (8% more biogas produced and a higher process stability). In the next period, the viscosity of the digestate in all test reactors will be determined.

During the first period of the DEMETER project, first results of testing the C1 enzyme in full-scale biogas plants have been achieved by Miavit. Therefore, evaluation of methods for testing the enzyme effects in full-scale biogas plants have been carried out. So far, seven biogas plants have been identified for the large scale trials. The first trials will start in March and May, the rest will start in September 2018. Biomoer, partner in the project will be one of the trial locations.

CIAOTECH has produced a first draft of the market analysis and techno-economic evaluation and all partners have been involved in giving input and suggestions.

Final results

DEMETER will bring innovation to both the fermentation process used for production of the enzyme, and to the use of enzyme-enhanced fermentation in production of biogas. Both levels of innovation are described in more detail below.

The C1 platform is an industrial platform to produce specific fungal enzymes to a very high titer and purity. This C1 system enables a highly efficient enzyme production with little to no unwanted or unneeded side activities. The platform allows for rapid expansion of specific enzyme activities, if application research in the coming period shows that a specific enzyme activity is needed to further improve the efficacy of the mixture. The development of the fermentation process for the C1 enzyme has been approached by analyzing the intracellular pathways of the production organism during the production of enzymes, which has resulted in the identification of nutrient limitations during fermentation that hamper production. All results obtained so far have been used to develop a mathematical model for the fermentation. In the coming period this model will be used to even further optimize the fermentation. The thus far optimized fermentation protocol has been tested on pilot scale and clearly showed improved yields. In the coming period this protocol will be transferred to industrial scale fermentations.

The yield of current biogas digesters still has a lot of room for improvement, such as increasing the rate of disintegration of the biomass feedstock, for which enzymes are an important tool. In DEMETER the effect of the C1 enzyme on the biogas process will be identified and quantified, and will be described in a numerical model. Lab scale trials and seven-eight field trials will be used to collect the data. The lab scale trials are currently running, whereas the field trials will be conducted in the coming period. This way, a model-based assessment of an individual biogas plant can be made, and the expected effect of the enzyme can be quantified in advance. This not only increases the specific effect of the enzymes, but also increases the economic impact. The innovations in this project will result in an increased competitiveness of biogas production by lowering the costs, enabling precise and tailor-made enzyme application, and increasing customer satisfaction.

Website & more info

More info: http://www.demeter-eu-project.eu/.