Kazan GAU: Technology for obtaining environmentally friendly fuel from straw

2024: Announcement of technology for obtaining eco-friendly fuel from straw

Kazan GAU scientists have developed a technology for obtaining environmentally friendly fuel from straw. This was announced on June 16, 2024 by representatives of the Kazan sky GAU.

source = Kazan GAU

As reported, a key factor in the efficiency of the developed technology is the optimization of the process of pretreatment of straw before fermentation.

{{quote 'author
= said Ilnur Gayfullin, Candidate of Technical Sciences, Senior Lecturer, Department of Machinery and Equipment in Agribusiness, Kazansky GAU' The choice of the pre-treatment method depends on a number of conditions and process parameters, such as the type of biomass, availability of equipment and energy costs. Efficient pretreatment makes it possible to use the potential of plant waste for the production of hydrogen biide and reduce the negative impact on the environment. As of July 2024, there is no universal optimal substrate pretreatment technology. Its purpose is to create such conditions for the composition of the medium, under which the strains-consumers of hydrogen are suppressed and the strains-producers are stimulated. However, some hydrogen - consumers may survive in substrates after pretreatment, and some hydrogen producers, by contrast, may be inhibited. This depends to a greater extent on the composition of the substrate culture medium, the presence of antiproductive substances in it and the metabolic processes occurring during fermentation.}}

Researchers Kazansky GAU conducted a series of experiments, during which they studied the influence of various methods of pretreatment of straw on the efficiency of subsequent fermentation and the yield of hydrogen biide. As a result, a two-stage technology was developed, involving steam-blasting of straw at temperatures of 165-210 ° C, followed by acid or enzymatic hydrolysis.

Steam blasting allows the structure of the lignocellulose straw complex to be destroyed, increasing the availability of cellulose and hemicelluloses for enzymatic hydrolysis. During hydrolysis, polysaccharides are broken down into simple sugars, which can then be used by bacteria to synthesize molecular hydrogen.

To ferment straw hydrolysates, the researchers used two strains of bacteria - Clostridium butyricum and Enterobacter cloacae, known for their ability to produce hydrogen. The optimal fermentation parameters for each strain were determined experimentally to ensure the maximum yield of the desired product:

• For Clostridium butyricum, the highest hydrogen yield (73 ml/g substrate) was achieved on acid hydrolysates of straw treated at 165 ° C, at a substrate concentration of 2%, a fermentation temperature of 37 ° C and a pH of 6.
• For Enterobacter cloacae, maximum hydrogen production (50 ml/g substrate) was observed on enzymatic straw hydrolysates obtained after steam blasting at 210 ° C, at a substrate concentration of 2%, a fermentation temperature of 36 ° C and a pH of 6.

The theoretical yield of hydrogen biide using the developed technology is up to 73 cubic meters of 1 ton of straw for the Clostridium butyricum strain and up to 50 cubic meters for the Enterobacter cloacae strain. At the same time, the cost of producing hydrogen biide from straw can be significantly lower compared to the use of traditional food raw materials such as glucose or sucrose.

The industrial introduction of the developed technology will not only reduce dependence on fossil fuels, but also solve the problem of agricultural waste disposal, reducing the negative impact on the environment. The results of the study are published in the scientific journal "Bulletin of Kazan State Agrarian University." Further research will focus on scaling the technology and optimizing pretreatment and fermentation processes.