Studies on fermentation parameters for production of industrial alcohol from broken and damaged rice grains
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Date
2011
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Punjab Agricultural University
Abstract
Two different isolates of Aspergillus sp. procured from starchy substrate (rice grain
flour) were screened for total amylase and glucoamylase activity. Among which Aspergillus
oryzae (green) was selected for the further study as it yielded maximum total amylase (20.15
U/ml) and glucoamylase activity (5.2U/ml) as compared to Aspergillus niger (black). This
Aspergillus oryzae (green) culture got accession no. HQ825090 after the identification at
molecular level by NCBI. The cultural conditions optimized by Response Surface
Methodology (RSM) according to Box-Behnken design comprising of five factors at three
levels for maximum total amylase production and glucoamylase production. The optimized
conditions for best enzyme production were found to be temperature 29.880C, pH 4.74,
moisture content 65.88% incubation time 3.78 and inoculum concentration 9.91%v/w Further,
liquefaction and saccharification of the rice grain powder was optimized by using varying
amount of the crude amylase and 8ml of crude amylase in 20% substrate concentration was
found to be best with maximum % saccharification about 79.95% after 6 hours of enzymatic
hydrolysis. Further, for simultaneous saccharification and fermentation, different fermentation
parameters were optimized by Response Surface Methodology (RSM) according to Box-
Behnken design comprising of four factors at three levels for maximum bioethanol production
by Pichea kudriavzevii (Issatchenkia orientalis) procured from CIPHET, Ludhiana identified
at molecular level by NCBI and available in public domain with accession no. HQI22942.
The maximum ethanol yield was found to be 69.25g/l in the Erlenmeyer flask fermentation.
The optimized cultural conditions for bioethanol by RSM were temperature 34.08°C, pH of
medium 4.8, aeration 126.13rpm and inoculum concentration 11.04%(v/v) containing 1x109
yeast cells/ml. Thus under optimized conditions scale up studies of bioethanol production was
carried out in laboratory scale fermenter of 2.5L capacity and results showed an slight
increase in the bioethanol yield of 71.68g/l with 90% fermentation efficiency as compare to
69.25g/l in the Erlenmeyer flask fermentation, as better controls in the fermenter throughout
the experiment
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Keywords
diseases,, thogens