Production of Nisin Z From Lactococcus Lactis IO-1 Using Sago Strach In Continuous Fermentation Mode

Maryana, Dahari (2018) Production of Nisin Z From Lactococcus Lactis IO-1 Using Sago Strach In Continuous Fermentation Mode. Masters thesis, Universiti Malaysia Sarawak(UNIMAS).

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Abstract

Nisin Z has been widely used in the food industry as a safe and natural preservative to increase the shelf time of many foods. The project was designed to produce high titres of nisin Z from L. lactis IO-1 by using hydrolysed sago starch (HSS) in continuous fermentation mode. Sodium azide was added to the media to maintain the sterility of the process. The outcome of the research found that the addition of sodium azide allows the system to last longer up to one-month fermentation. As the system can last longer, higher productivity can be produced. Sodium azide is a toxic product especially to human then; it needs to be removed by using dialysis before further tests were done. Under the conditions tested, a titre of 3200 AU Lh-1, nisin Z activity was produced. Apart from the study also discovered the antimicrobial activity of nisin Z was still being produced even in contaminated culture, but the production decreased as the biomass of L. lactis IO-1 was reduced. Therefore, the contamination was a barrier to maintain long-term fermentation. As for the recovery, nisin Z was recovered by ammonium sulphate precipitation shows higher recovery with 274.712 μg mL-1 compared to acetone precipitation, 134.160 μgmL-1. Clearly, continuous culture using HSS with supplementation of sodium azide and purification by ammonium sulphate is a good approach to maintain long-term fermentation because it could reduce labour and cost effective since glucose can be easily extracted from the sago starch.

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