The growing demand for innovative and differentiated products has propelled many experts in the search for other types of non-Saccharomyces yeast to develop specialty beers. Although they usually have low fermentative yield and are more sensitive to ethanol, many of these yeasts promise to have a distinctive taste and aroma characteristics. Although many of them have already been characterized as contaminants of fermentation processes and potential alterants in fermented beverages, some species are now emerging as valuable producers of aromatic esters in well-monitored and well-controlled processes.
The possibility of exploitation of these microorganisms can be quite varied. Depending on the product to be obtained, they can be used either as pure inoculants in place of conventional yeast, as co-inoculation (different microorganisms added at the same time) or sequential inoculation.
This work aimed to analyze the kinetics of S. boulardiigrowth in an airlift fermenter under two aeration conditions: 1 and 1.5 air vvm (air volume per volume of culture medium per minute), in comparison with growth in shaken flasks, with a view to the future application of this fermenter on an industrial scale. Airlift fermentors offer advantages such as efficient homogenization of the components, low shear stress, and energy savings because the medium is stirred by aeration and does not require mechanical stirring. The pH of the medium decreased with the glucose uptake during the exponential phase, probably due to the formation of secondary metabolites. The entire process showed a similar specific growth rate during the exponential phase (up to 5 hours in the case of the shaker and 6 hours in that of the air-lift fermentor), indicating a possible change in the carbon source since all glucose was depleted after the aforementioned periods. After 6 hours, the growth rates in the shaker and the fermenter were similar under 1.0 vvm, but lower than in the fermenter under 1.5 vvm, suggesting that the fermentor may reach a higher cell production rate depending only on the oxygenation efficiency.
In operations, the company changed its planting calendar. It will now concentrate on activity from December to March when the most productive varieties (which grow in 18 months) are planted. The goal is to maintain the sugarcane renewal rate at 13% of the cultivated area each year, ensuring that the sugarcane trees have an average age of four years, said Ricardo Lopes, Biosev’s director of operations and origination.
Another step was to focus on sugar and alcohol products and eliminate those that were not “adequate” at low prices. As a result, the company stopped producing white sugar in three mills and yeast at the Leme mill (SP), in addition to animal feed and molasses powder. With these interruptions, steam was “leftover” for the production of anhydrous ethanol and electricity.
Now the fine comb is being made on the farms, which encompass 346,000 hectares of sugarcane. “In the 1990s, the agricultural cost was variable. Today, two-thirds of the agricultural cost is fixed for cutting, harvesting, and transport,” said Chammas. This whole plan supports the prospect of reducing this season’s CAPEX to R $ 1.25 billion (with a “margin of error” of R $ 90 million), compared to R $ 1.38 billion last season.