By Camila Souza Ramos – From São Paulo
The Brazilian production of cellulosic or second-generation (2G) ethanol has been struggling with technological challenges and lack of incentives for years. Now it may gain momentum again with brand new innovations that have just become available.
The National Laboratory of Biorenewables, of the National Research Center for Energy and Materials (LNBR/CNPEM) – a social organization under the Ministry of Science, Technology, Innovations and Communications (MCTIC) – has just created an enzymatic cocktail with genetically modified fungi that can be manufactured within the plants themselves and at lower costs, which is likely to make the entire production process easier.
The novelty adds to another achievement that has been recently announced by Embrapa and the Sugarcane Technology Center (CTC), which also created a cocktail based on three microorganisms, including GMOs. The LNBR research, however, has already been replicated in a pilot plant and is closer to being launched on the market due to patents in advanced registration process.
Enzymes are a central element in the production of cellulosic ethanol in Brazil, since they are responsible for the breakdown of sugarcane biomass (straw and bagasse) and its transformation into sucrose. Currently, the two 2G ethanol plants in the country – one by Raízen Energia and the other by GranBio – only use imported enzymes manufactured abroad by three companies.
The main advantage of domestically-manufactured enzymes is the reduction of costs in the production of cellulosic ethanol, which are still considered a barrier to the competitiveness of biofuel. Enzymes account for about 30% to 40% of the production costs.
This percentage depends on the level of technology used in the plant and whether or not there is integration with conventional ethanol production. Overall, the cost of enzymes for 2G ethanol ranges from USD 4 to USD 10 per kilo. "Our modeling indicates that the cost [of the LNBR cocktail] is below this lower limit – depending on the process, it is of about USD 3 [per kilo]," said Mario Murakami, research leader at the laboratory.
LNBR is patenting its fungus – genetically modified to produce the desired enzymes for the hydrolysis (breakdown) of biomass – and also the bioprocess for producing the enzyme. On the platform they created, the fungus digests organic inputs produced as waste in the plant's own industrial process, like molasses and yeast.
"The genetic modifications were made with the integration of the Brazilian sugar-energy industry in mind," said Murakami. However, there is nothing to prevent the technology from being used on other 2G ethanol production routes that are common in other countries, where rice straw and forestry waste are used as raw materials, for example. The enzymatic cocktail can also be used in other production chains, such as animal feed, food and drinks.
“Each architecture [of cellulose in biomass] requires fine tuning of the cocktail composition. I make this adjustment by increasing or reducing an enzyme, by "switching it off" [in the genetic modification process]. Our fungus is fully domesticated,” he said.
One of the main cost reduction factors is the high productivity of enzymes that a company can achieve in its own plant. The LNBR fungus strain obtained a yield of 80 grams per liter of enzymes, which represents a conversion rate of waste to enzyme of 40%. The rate of conversion of enzymes described in the scientific literature varies from 5% to 25%. Furthermore, the efficiency of the laboratory's enzymatic cocktail is similar to that of commercial enzymes in the process of saccharification (turning biomass into sucrose), said the researcher.
For a plant that wants to invest in cellulosic ethanol with its own production of enzymes based on LNBR technology, an investment of “a few dozen million reals” is required in equipment. This may vary according to industrial capacity and type of treatment given to the biomass, among other factors, according to Murakami.
Although the initial investment can be high, return can come in several ways. For a plant to buy the enzymes available today, it bears the costs of import, refrigeration during transport, storage and downstream.
Both LNBR patents have already received favorable international opinions and are awaiting final registration before licensing can begin. Since the laboratory is a non-profit organization, there are conversations with companies to make the technology available on the market.
Embrapa and CTC have applied for the patent of their cocktail in November and are looking for companies capable of producing it on an industrial scale.