Embrapa Agroenergy –The lignocellulosic ethanol obtained from the breakdown of the polymer chains forming the fibrous structure of the plant by means of chemical or biochemical reactions, is still not produced on a large industrial scale. This is due to certain factors, but mainly the economic. In order to solve the problem, Embrapa Agroenergy, together with other research centers, launched the project “Superior Microbial Strains for the Production of lignocellulosic ethanol,” which aims to increase the efficiency of hydrolysis of biomass and improve use of sugar fermentation, thus lowering production coast.
According to João Ricardo de Almeida, a researcher from Embrapa Agroenergy, the project is to obtain genetically improved microbial strains for use in production processes of ignocellulosic ethanol.
– Specifically we seek to obtain strains of filamentous fungi producers of hydrolytic enzymes and yeasts for fermenting pentoses and hexoses (sugars with 5 and 6 carbons,, respectively) states Ricardo.
This project started, officially, in January 2012. However, the partners are already involved in working on the topic for several years. The activities were divided between researchers from different institutions. Besides the Embrapa Agroenergy are four other research units, including Embrapa Agro Food, Embrapa Environment, Embrapa Genetic Resources and Biotechnology and Embrapa Grape and Wine. Also the Oswaldo Cruz Foundation, the National Institute of Technology and the Federal University of Rio de Janeiro (UFRJ) is part of this project.
In this project, researchers from Embrapa Agroenergy, along with the Embrapa Food, will use a classical breeding technology and also genetic engineering technique even metabolic engineering, for obtaining more efficient strains of Trichoderma sp. and Aspergillus sp, which are producers of hydrolytic enzymes and yeast fermenters of pentoses. In subsequent steps, these strains will be characterized and evaluated by the different partners of the project – explains the interviewed.
Still according to him, the microorganisms operate in different stages of production. He reports that filamentous fungi are excellent producers of hydrolytic enzymes, which are responsible by the release of sugars from lignocellulosic biomass. That is, the enzymes break the complex structure of lignocellulose and release sugar monomers which may then be converted during the fermentation into ethanol, the next step of the process.
– With the breeding of lineages of filamentous fungi in this project, expected to get enzymes in higher concentration and more efficient in the hydrolysis of lignocelluloses. Already yeasts, act on the conversion of sugars into ethanol, a process known as fermentation. Thus, the yeast microorganisms are also essential for the ethanol production. The yeast genetic improvements allow the higher yield in ethanol lignocellulose production, since the sugars present in the substrate will be better utilized by the yeast – account.
For Almeida, the expectation is the attainment of lineages of Trichoderma sp., Aspergillus sp. producers of hydrolytic enzymes and yeast fermenters of pentoses more efficient. Moreover, there are certain obstacles.
– The high cost of hydrolytic enzymes and the difficulty of fermenting the pentose (5 carbon sugars) are now two major barriers for the ethanol lignocellulosic production on an industrial scale. The achievement of producing strains of hydrolytic enzymes Superior will increase the efficiency of hydrolysis of biomass and simultaneously reducing the cost of the enzymes. Moreover, yeasts genetically improved allow an increase in the ethanol yield in the process, since sugars are used more efficiently – explained.
There is no ethanol lignocellulosic production on an industrial scale, mainly because the process is not yet economically viable. In this sense, he asserts that this project is come to add, justly for tackling two major challenges of the process.
– The most efficient hydrolysis of the sugar from the biomass and better use of the fermentation must lower the production costs, however, cannot be established percentages due to the great complexity of the process as a whole – says.
Source and Photo: Portal Dia de Campo, January 13rd, 2012
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