Short Communication ISSN: 2321-2969
Received: 13 April 2013, Accepted: 23 April 2013 Int. J. Pharm. Biosci. Technol.
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International Journal of Pharma Bioscience and Technology, Volume 1, Issue 1, May 2013, Pg 50-53
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FERMENTATIVE PRODUCTION OF ETHANOL FUEL FROM DOMESTIC
WASTE BY PICHIA STIPITIS
Department of Biotechnology, DVR & Dr. HS MIC College of Technology, Kanchikacherla, A.P. INDIA.
E-mail address- email@example.com
Production of Ethanol fuel from the garbage/kitchen waste was carried out with the main purpose of
converting the domestic waste into a useful material. The conversion of food waste or garbage by acid
hydrolysis was carried out to obtain fermentable sugars, which was converted into ethanol by
fermentation process using Pichia stipitis. The present study indicated that at 36 h of incubation resulted
in utilization of 29 g/L of glucose with yield of 9.2 g/L ethanol. Compared to various sugars the glucose
resulted in the production of ethanol.
Key words: Ethanol fuel, Garbage, Pichia stipitis, Biomass, Fermentation; Conversion
contributes more than 58% to the production cost,
Ethanol or ethyl alcohol is a volatile, flammable,
inexpensive feed stocks such as lignocelluloses
colorless liquid. A psychoactive drug and one of
biomass and agricultural food wastes are being
the oldest recreational drugs known, ethanol
considered to make bio ethanol competitive in the
produces a state known as alcohol
open market . Lignocellulose is the major
intoxication when consumed in excess. Best known
structural component of woody plants and non
as the type of alcohol found in alcoholic
woody plants such as grass and represents a major
beverages, it is also used in thermometers, as
source of renewable organic matter in the soil .
a solvent, and as a fuel. In common usage, it is
Large amounts of lignocelluloses waste are
often referred to simply as alcohol or spirits. The
generated through forestry and agricultural
production of ethanol has two routes synthetic and
practices, paper-pulp industries, timber industries
biological. The synthetic ethanol production is
and many agro industries and they pose an
commonly carried out by a catalytic hydration of
environmental pollution problem. Unfortunately
ethylene in vapor phase and often as a by product
much of the lignocelluloses waste is often
of certain industrial operations . Ethanol is
disposed of by biomass burning, which is not
produced from fermentation of sugars extracted
restricted to developing countries alone, but is
mostly from crops. Saccharomyces cerevisiae is the
considered a global phenomenon . Thus
most popular organism used for ethanol
enzymes have significant potential applications in
production due to its high ethanol yield and high
various industries including chemicals, fuel, food,
tolerance. Now a days crops are the main source
brewery and wine, textile, animal feed etc.
used for ethanol production [2,3]. Current
Basically lignocelluloses biomass comprises of
industrial processes for bio ethanol production
cellulose, hemicelluloses and lignin . The
uses sugarcane or cereal grain as feed stocks, but
structure of the cellulose is rigid and harsh
they have to compete directly with the food sector
treatment is required to break it down . Hemi
. Although these are the predominant feed
cellulose consists of short, linear and highly
stocks that are used today, projected fuel
branched chains of sugars . Ethanol
demands indicate that new, alternative, low priced
production has been taken into estimation
feed stocks are needed to reduce ethanol
depending upon the ratio of hexoses and
production costs . Since the cost of feedstock
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Int. J. Pharm. Biosci. Technol.
pentoses. Pichia stipitis is predominantly haploid, The solid substrate in the form of
heterothallic yeast related to pentose metabolizing garbage/kitchen-domestic waste was washed with
ascomycetes (Fig. 1). Strains of this species are water for 2-3 times and then allowed for sun
one of the best xylose fermenting yeasts in type drying for one day and then kept in hot air oven at
culture collections. Increasing the capacity of 50º C until it was completely dried and used for
these species for rapid xylose fermentation could acid hydrolysis. Cellulose can be converted to
enhance the productivity and sustainability of fermentable sugars by concentrated sugars.
agriculture and forestry by providing new outlets Concentrated acid processes generally give
for agricultural and wool harvest residues. higher sugar yield and consequently higher
ethanol yield compared to dilute acid processes.
Estimation of reducing sugars
5 g of NaOH were added to 400 ml of distilled
water and by continuous stirring 100 g of sodium
potassium tartarate was added. After that 250 mg
of sodium sulphite, 5 g of DNS and 1 ml of phenol
were added to the solution. Then it was filtered
and kept under constant stirring in dark room to
avoid the exposure of DNS to light. The reagent
was kept in a dark and cold place as DNS is light
Fig. 1. Haploid cells of Pichia stipitis sensitive.
Agricultural productivity would be greatly Reducing sugar’s standard preparation
improved and incomes for famers would increase
if there were larger markets for agricultural The stock solution of 1000 μg/ml was prepared in
residues. Unlike yeast which regulates distilled water. From this stock solution, dilutions
fermentation by sensing the presence of were prepared ranging from 100 μg/ml to 1000
fermentable sugars such as glucose, it induces μg/ml. 1 ml of DNS reagent was added to 1 ml of
fermentative activity in response to oxygen each dilution in separate test tubes. The mixture
limitation. was vortexed well and kept in boiling water bath
for 10 min. After 10 min the mixture were cooled
MATERIALS AND METHODS down and absorbance was read at 540 nm against
the blank containing 1 ml of distilled water instead
A loop full of cells were added to each 250 ml of of glucose dilution.
flasks containing 150 ml of sterile culture media
containing - glucose 50 g/L, yeast extract 4 g/L, Estimation of Ethanol
peptone 5 g/L, KH2PO4 1.5 g/L and MgSO4 0.5 g/L,
were incubated in a rotary shaker at 30º C and at The amount of Ethanol was determined from the
300 rpm for 24 h. Substrates used are garbage i.e. supernatant according to the method described
vegetable waste, fruit waste collected from the by Caputi et al. 
local markets. The vegetables and fruits used are
potatoes, Pineapples, Brinjal, Grapes, Apples, Potassium Dichromate solution
Oranges and Bananas. The substrate collected was 3.4 g of potassium dichromate was added to 6.6 N
initially separated into solid and liquid by of sulfuric acid. 5 ml of potassium dichromate
squeezing the substrate and resultant filtrate was solution was added to 1 ml of cell free culture
subjected to auto hydrolysis and the solid waste filtrate and mixed well. The reaction mixture was
were subjected to acid hydrolysis. kept at 60º C for 20 min in the water bath. Then the
O.D was read at 600 nm after cooling it and
Auto hydrolysis concentration of ethanol was determined by
Liquid faction which contains sugars are placed in computing the O.D. against the standard curve
an amber bottle and left for 7-10 days and filtered. which was prepared using concentration of 0.2%
The filtrate was added to the production media for to 2.5%.
ethanol along with Pichia stipitis.
RESULTS AND DISCUSSION
Acid hydrolysis of garbage to produce
fermentable sugars Pichia stipitis increases the ethanol production at
5% concentrated sulphuric acid hydrolysate at
temperature of 20º C to 30º C, pH 5.5. The effect of
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Int. J. Pharm. Biosci. Technol.
various carbon sources on the ethanol production concluded that glucose liberated by hydrolysis of
using this Pichia stipitis was estimated by adding garbage/domestic waste, produced maximum of
various carbon sources (Fig 2). The effect of alcohol after 36 h of incubation.
various carbon sources on the ethanol production
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Modugu P Pg. 52
Int. J. Pharm. Biosci. Technol.
How to cite this article
Modugu, P. (2013). Fermentative Production of
Ethanol fuel from Domestic Waste by Pichia
stipitis. International Journal of Pharma
Bioscience and Technology, 1(1), 50–53.
Elsevier Harvard style
Modugu, P., 2013. Fermentative Production of
Ethanol fuel from Domestic Waste by Pichia
stipitis. Int. J. Pharm. Biosci. Technol. 1, 50–53.
Modugu P. Fermentative Production of Ethanol
fuel from Domestic Waste by Pichia stipitis. Int.
J. Pharm. Biosci. Technol. 2013;1(1):50–53.
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