2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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TechConnect Summit
Clean Technology 2008

Nutrient recovery from soybean whey, a waste stream from soybean processing industry, by lactic acid bacterial fermentation and subsequent nisin production

D. Mitra, A.L. Pometto III, S.K. Khanal and J. van Leeuwen
IOWA STATE UNIVERSITY, US

Keywords:
Soybean whey, nisin, Lactococcus.lactis

Abstract:
The objective of this study is the evaluation of low/negative value soybean whey as an alternative, inexpensive substrate to grow Lactococcus lactis and produce nisin, an FDA approved bio-preservative. One-third (wet-weight basis) of every kilogram of soybeans ends up as soybean whey during extraction of soy protein isolate. The disposal cost of such large volumes of waste stream is substantial owing to its high chemical oxygen demand (COD=25,000 mg/L). L.lactis is a nutritionally fastidious organism and fortuitously, our research lab is the first to demonstrate that its growth and subsequent nisin production can be supported by soybean whey. Batch tests were done in 200-ml Erlenmeyer flasks and samples were taken periodically and analyzed for biomass, lactic and acetic acids and nisin concentrations. We have achieved a biomass yield of 2.18 g/L and nisin yield of 619 mg/L. Supplementation of the soybean whey with micronutrients and sucrose led to 26 and 8% increase in biomass yields, respectively. Thus, crude soybean whey could be used directly as a nisin production medium. This study successfully shows the possibility of adding value to a waste stream by microbial utilization/ extraction of residual nutrients and recovery of an important product.


Nanotech 2008 Conference Program Abstract