Effect of nutrient supplementation on single cell protein production from watermelon and pineapple peels

Abstract

The world fast growing populated countries have presented an increased demand for protein rich food. This exerts great pressure on food and feed industries to produce enough protein with economical value to meet the demand. However, fruit production is on increase worldwide generating large amounts of fruit wastes which lead to pollutions in both Agricultural and fruit processing industries. This problem along with increased worldwide protein requirement stimulates the interest in converting fruit wastes into commercially single cell protein. In the present study, efforts were made to improve growth support capacity of watermelon and pineapple fruit wastes by submerged fermentation using Saccharomyces cerevisiae. Saccharomyces cerevisiae produces higher amount of Single Cell Protein by submerged fermentation of pineapple peel hydrolysate (9.8%) as compared to watermelon peel hydrolysate (2.42%). It was also observed that, the combination of the two fruit wastes produce higher Single Cell Protein than watermelon but lower than pineapple fruit waste. However, additions of nutrient supplements (Glucose and Ammonium sulphate) greatly increase Single Cell Protein production in all the fruit combinations and the absence of any of Glucose or Ammonium sulphate greatly affects Single Cell Protein production. This negative effect is higher when Ammonium sulphate is excluded probably due to their low protein content of the fruit wastes (6.40% and 3.50% for watermelon and pineapple wastes respectively) than when Glucose is excluded. This suggested that microbial growth support capacity of fruit wastes can best be improved by addition of Nutrient supplements rather than combining different fruit wastes.