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Assessment of ethanol expediting activity of spoilt wheat bacteria

KrishiKosh

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Title Assessment of ethanol expediting activity of spoilt wheat bacteria
 
Creator Sharma, Adarsh
 
Contributor Dhamija, S.S.
 
Subject Alcohols, Wheats, Productivity, Enzymes, Fermentation, Grain, Yeasts, Bacteria, fFungi, Starch
 
Description Ethanol besides being a known feedstock for chemical and beverage industry is also being used as an additive to fuel for automobiles. Over the years, its demand in general, has been on an increase and India is no exception. Clearly, maximization of ethanol production becomes imperative and could be achieved by considering, among others, the addition of yeast nutrients to the fermentation liquor. These nutrients by accelerating the rate of fermentation reduce the fermentation time and in turn lead to maximization of ethanol volumes on a daily basis. Usually, N and P represent these nutrients and in the Indian distilleries they are conventionally sourced from chemical fertilizers, which do have a certain carbon footprint. Ideally, organic/ renewable yeast nutrients would be more suitable, as they have a low net green house gas emission. However, so far, no dedicated nutrient formulation is available in the Indian market.
Spoilt wheat which ferments faster than its normal version has been shown to offer a potential for such a formulation, as it contains factor(s)/activity that is responsible for expediting rate of ethanolic fermentation. This ethanol-expediting activity has been speculated due to in situ production of yeast nutrients viz., low molecular weight peptides and free amino acids by the activities of resident bacterial and fungal flora of spoilt wheat. So, bacterial flora of spoilt wheat was screened for its ethanol-expediting capability, leading to the retrieval of the best isolate. Such an isolate might later contribute to the development of more useful, environment friendly and activity-enriched wheat-based supplements to expedite ethanolic fermentation by yeast.
The spoilt wheat (SW) sample tested positive for ethanol-expediting activity on 30% normal wheat (NW) hydrolysate, as its supplementation @ 15%, both as coarse flour or its aqueous extract, produced 10.6% and 11% (v/v) ethanol, respectively, against 8% (v/v) by the control. Clearly, the SW sample under study was fit for isolation of bacteria. Based on colony morphology, 60 bacterial isolates were recovered from the SW sample. While 32 of the isolates turned out to be Gram positive and 27 Gram negative, one appeared Gram variable. Twenty-two of the 60 isolates emerged spore formers. Screening of the isolates for amylolytic and proteolytic activities on the plate revealed 31 isolates to be positive for the former and 15 for the latter. Thus, only five bacterial isolates viz., SWB-11, SWB-29, SWB-50, SWB-53 and SWB-60 having dissolution factor of >2 were further utilized to explore their ethanol-expediting capabilities by producing laboratory spoilt wheat grains and subsequently estimating ethanol production by yeast on 30% NW supplemented with the former as flours @ 15% (w/w). Ethanol estimation at 24-h showed that three isolate viz., SWB-11, SWB-29 and SWB-50 did produce a boost to alcohol production from 8% to 9% (v/v). These three isolates based on morphological and biochemical characterization were identified to belong most probably to genera Pseudomonas, Enterobacter and Micrococcus, respectively.
 
Date 2016-10-28T11:50:59Z
2016-10-28T11:50:59Z
2012
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/82693
 
Language en
 
Format application/pdf
 
Publisher CCSHAU