NEW TRENDS FOR ENVIRONMENT: DISPOSAL FROM DAIRY INDUSTRIES APPLIED IN NISIN PRODUCTION

Angela Jozala (FCF/USP); Luciana Arauz (FCF/USP); Priscila Mazzola (UNICAMP); Adalberto Pessoa Jr. (FCF/USP); Thereza Christina Vessoni Penna (FCF/USP)

In the last years, disposal from dairy industries have received a special attention due to its polluting impact in the environment. For this reason, studies have obtained a positive support to develop different alternatives to recycle milk whey components. One of them is its utilization as culture media, aiming to produce biomolecules with noble applications. Nisin production employing milk whey as culture media was evaluated in this study. Nisin is an extracellular peptide, it has a molar mass of 3.4 kDa, and it is produced by Lactococcus lactis, this peptide has been applied as a natural additive once it presents broad antibacterial activity against Gram-positive and negative microorganisms, as well as spores. Many researches list potential nisin applications including dental care treatment, stomach ulcers, colon infection and potential birth control. Previously to fermentation assays, milk whey had pH adjustment with NaOH (1M), after that it was separated in glass bottles to submit sterilization under 121°C for 15minutes. L. lactis pre culture was developed in 150mL of MRS broth, at 100rpm, 30°C for 36h. The pre culture was poured into 1.5L of the milk whey (pH 6.8) in a 2L bioreactor. The bioreactor conditions were 30°C, variation of agitation (AGT) in 100 and 200rpm; and airflow rate (AIR) in 0, 1 and 1,5 L.min^-1. Nisin activity was quantified by agar diffusion assay utilizing L. sakei ATCC 15521 as a sensitive indicator microorganism and expressed in arbitrary units (AU.mL^-1 of medium). Culture media composed by milk whey offered ideal conditions to L. lactis development and nisin biosynthesis. The AIR combined with AGT proved to be a main factor to nisin release. In the assay with fixed AGT in 200rpm and AIR=0 nisin activity detected was 7 logAU, 2.3 times higher than when AIR=1.5 and AIR 1. Reproducing theses assays with fixed AGT in 100rpm, it was verified that nisin activity was reduced 2 times when compared with the assay 200rpm, with AIR=0. Nisin activity was around 7 logAU, when applied AIR=0.5, same result was obtained in the assay AIR=0 and AGT=200rpm. Comparing all results the condition to work out for nisin production was without airflow rate and 200rpm. The utilization of milk whey as substrate allow to reduce production costs of nisin, besides it contributes to industrial disposal recycling, thereby, diminishing the environment pollution, and encouraging the government and industries to support scientific researches.