physicochemical

J.Res. ANGRAU 39(1&2)6-9, 2011
SCREENING OF YEAST ISOLATES AND PRODUCTION OF ALCOHOL FROM OVER
RIPENED SAPOTA FRUIT PULP
YELPALE MANOJ MARUTI, R. SUBHASH REDDY, S. J. RAHMAN and S. SOKKA REDDY
Department of Agricultural Microbiology and Bioenergy,
College of Agriculture, Acharya N.G. Ranga Agriculture University,
Rajendranagar, Hyderabad-500 030
ABSTRACT
Ethanologenic yeasts were isolated from different sources like spoiled fruits, market yard wastes, industrial
wastes and orchard soils. Cultures were identified and screened for alcohol production, AMY-2 was found to be the
best among the isolates. Over ripened sapota fruit pulp with reducing sugars 7.62 (g 100g -1 ), total sugars 11.85 (g
100g -1 ), total soluble solids 19.50 ( 0 Brix) and pH 5.4 was used for fermentative production of alcohol. About 30.17-
67.00 (g L -1 ) of alcohol was obtained when fermentation was conducted at different pH’s (4.0, 4.5, & 5.0), temperatures
(ambient temp.- 30-38.6 0 C & controlled temp.- 26 0 C) and with cultures (standard culture Saccharomyces cerevisiae-
MTCC-172 & local best isolate AMY-2) for 72 h. It is established that over ripened sapota fruits can be used
effectively for fermentative production of alcohol at pH 5.0 and temperature 26 0 C as fermentation conditions in 24 h.
The total area under sapota cultivation in
India is 1,56,100 ha, with a total production of
13,07,800 MT and total productivity of 8.4 MT ha -1
during the year 2008-09 (Indian Horticulture Database,
2009). The post harvest losses of the fruits, were
estimated to be about 30-40%, in general, due to
several reasons which accounts to a loss of around
6,750 crore rupees every year. Sapota fruit is highly
perishable in nature, requires a quick disposal and in
glut period a large quantity of the fruit is wasted.
Hence, marketing of sapota becomes a serious
problem. The Sapota fruits are good source of sugars,
which range from 12 to 18 % and appreciable amount
of protein, fat, and minerals like calcium, potassium,
iron etc (Gautam and Chandawat, 1998) are found in
the fruits. Because of its high sugar content the over
ripened or spoiled sapota fruits can be used in a
profitable manner. One of the approaches is
fermentative production of alcohol from over ripened
Sapota fruits.
In view of fast depletion of fossil fuels and
environmental pollution due to gaseous emissions,
alternative fuels such as bioethanol and biodiesel are
becoming important.
Biofuel such as alcohol is obtained by
microbial fermentation of plant biomass to generate
the green fuel. Currently, there is a growing interest
for ecologically sustainable bio-fuels, such as alcohol
produced by fermentation from renewable sources
as fuel or fuel additive. Among all the sustainable
alternative fuels, ethanol is an important fuel source,
which is renewable and reduces the green house
effect, global warming and climate change (Demirbas,
2003).
The present investigation was carried out
with the objective of isolating ethanologenic yeasts
from different sources and to check the suitability of
sapota sugars for alcohol production, in addition to
giving some economic returns to farmers even from
over ripened or spoiled fruits during market glut etc.
MATERIALS AND METHODS
The yeast strains were isolated from different
sources like spoiled fruits, market yard wastes,
industrial wastes and orchard soils following spread
plate technique under aseptic conditions. The
samples were inoculated on to Sabouraud Dextrose
Agar medium and incubated at 37 0 C for 24-48 h.
All the isolates obtained from different
sources and standard culture were screened for
alcohol production with sugar as a fermentation
medium (23 0 B) so as to choose the best isolate for
alcohol production. 200 ml of sugar medium was
taken into the bottles for fermentative production of
alcohol. All the bottles were pasteurized at 82 0 C for
30 minutes and rapidly cooled at room temperature.
The yeast inocula were transferred to the pasteurized
E mail : manoj_yelpale@yahoo.com
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