Characterization of Dairy Waste Whey and Its’ Utilization for the Production of Ethanol
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Date
2018-06-06
Authors
Journal Title
Journal ISSN
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Publisher
AAU
Abstract
The objective of this study was characterization of dairy wastes (cheese whey) and its utilization
for the production of bioethanol. The key to the utilization of this resource has been changing the
perception of cheese whey from a 'waste material' to an 'opportunity' for further processing. Dairy
cheese whey consisted of biological oxygen demand (BOD = 230mg/mL) and chemical oxygen
demand (COD = 70mg/mL). It represents largely disaccharide sugar content lactose (0.036 – 0.048
mg/mL or 3.36 – 4.48 %) and thereby, it is managed by converting into bioethanol with the help
of yeast strain. In this work, kluyveromyces delphensis yeast strain was used for bioethanol
production from cheese whey in batch fermentation (Erlenmeyer flasks). The composition of
cheese whey was determined and characterized to identify its impacts on environment. The
experimental design was studied with central composite design (CCD) to investigate the effects of
significant factors including initial lactose concentration (4.5, 6.15 & 7.8g/L), yeast cell
concentration (5, 7.5 & 10g/L), temperature (27
o
C, 31
o
C & 35
o
C) and pH (5, 5.5 & 7) on
fermentation process. The response surface methodology (RSM) was applied to investigate the
interaction effect of fermentation process variables and to achieve maximium yield of bioethanol
from cheese whey. The best operating conditions were found to be initial lactose concentration
6.15g/L, yeast cell concentration 10g/L, temperature 27
o
C and pH 5.5. Under this condition, 15.5
mL of bioethanol per 500mL of cheese whey was fermented as a final point. The maximum ethanol
yield obtained from cheese whey was 20.4 %. The functional groups of cheese whey Bioethanol
were determined by using FT-IR with the help of IR correlation charts and moreover, the
characteristics of bioethanol was investigated. This ascertained that the product obtained from
cheese whey is definitely ethanol due to the confirmation of regions. Consequently, cheese whey
is a good resource for production of bioethanol.
Description
Keywords
Bioethanol, Cheese whey, Fermentation process, Kluyveromyces delphensis yeast