Abstract
Apart from creating many positive impacts, the growth of agribusiness has also generates concerns about the production of large amounts of undervalued by-products. Cheese whey and corn steep liquor (from corn flour production, a typical Brazilian food) are among these by-products that can be potential raw materials for obtaining new products such as bioethanol. The objective of this study was to apply an experimental design tool to examine different worts with cheese whey and corn steep liquor for the production of bioethanol. The worts containing 100 % corn steep liquor, and 25 % cheese whey with 75 % corn steep liquor supplemented with glucose were considered the best for the production of bioethanol, with fermentation efficiency reaching around 90 % for both of them. The use of pasteurization and antibiotics was effective in controlling lactic acid production, which results from bacterial contamination. The use of antibiotics showed advantages by reducing the maximum growth rate of yeast, which was reflected in higher rates of fermentation efficiency. The results obtained allowed reaching a high level of ethanol productivity.
Highlights
Petroleum is a finite source of energy and always involved with environmental degradation issues
Intensive scientific studies are needed to find a highly productive process by using inexpensive and renewable substrates, including food industry by-products such as corn steep liquor (CSL) and cheese whey (CW) (AMORIM et al, 2011; CHOI et al, 2010; DODIĆ et al, 2009; LEITE et al, 2008; MOREIRA et al, 2015)
Cheese whey (CW) is the liquid by-product of milk coagulation in cheese production; it is generated in large quantities, around nine liters of CW per kilogram of processed cheese, and has a high organic load, which is attributed to its high lactose content (7075 %, dry matter) (CARVALHO; PRAZERES; RIVAS, 2013; GUIMARÃES; TEIXEIRA; DOMINGUES, 2010)
Summary
Petroleum is a finite source of energy and always involved with environmental degradation issues. In order to reduce this impact, bioethanol can be produced from alternative sources such as agro-industrial by-products This seems very promising, the high cost of this type of fuel is a limiting factor in commercial use. Corn wet-milling in Brazil is used to obtain "Biju" corn flour, a typical and widely-consumed food in the country In this form of processing there is no addition of sulphur dioxide and the CSL that is derived has about 8 % (w w-1, dry matter). This type of CSL is produced in large volumes, around one liter per kilogram of corn processed, and there are no studies that indicate its possible uses (LOSS et al, 2009). The mixture of the Brazilian Journal of Food Research, Campo Mourão, v. 7, n. 3, p. 150-172, set./dez. 2016
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