Projeto industrial de produção de ácido lático utilizando permeado de soro de leite como substrato para a fermentação

Abstract

The extensive dairy production in Brazil has provided a considerable growth of dairy products in the South and Southeast, causing social and economic impacts to these places. Along with the milk processing, various methods of producing additional dairy products have been developed in order to increase the profitability dairy supply chain. Among these derivatives, one of the most widespread is the cheese, which production involves a pressing step of milk, which ends up producing large amounts of cheese whey, a by-product of high organic load and difficult to treat by conventional methods (stabilization ponds or physicochemical methods). This by-product has been used to obtain whey protein, widely used as a dietary supplement and commonly obtained through membrane separation processes, generating as a residue the whey permeate, which has been widely studied as a culture medium for fermentative processes due to their high concentration of lactose and mineral salts. Amongst the potential products that can be obtained through the fermentative process of this raw material the lactic acid stands out due to its wide use, such as in the chemical, food and polymer industries. In this context, the objective of the present project was to evaluate the viability of fermentative production of lactic acid using cheese whey permeate as substrate. To this end, a market research was initially conducted regarding the demand for lactic acid and the availability of raw materials and process inputs. Following, based on literature research the mostly common operating conditions including mainly used microorganism, namely, Lactobacillus sp. RKY2, and batch operation configuration. The process flow (PFD) and piping and instrumentation (P&ID) diagrams were then developed; the mass and energy balances for each operation, in addition to the plant layout. From this, the main equipment needed for the process were dimensioned in order to determine the capital (CAPEX) and operating costs (OPEX) of the plant. Consequently, a cash flow simulation was performed to assess the viability of the process. Overall, the cash flow analysis evidenced a high accumulated cash flow (53.64 M$), with a 38 month payback time and a high net present value (NPV), attesting to the economic viability of the project and the potential use of this by-product for its valorization in the fermentative lactic acid production.