Abstract:
This study was aimed to determine the ethanol potential of prosopis juliflora pod by
fermentation using saccharomyces cerevisiae yeast. The milled p.juliflora pod was
hydrolysed by distilled water and by dilute sulfuric acid (0.2, 0.4, and 0.8 M) at
temperature of 90°C for 15 and 30 minutes. The result showed that the maximum glucose
(113.2 g/l) was obtained from hydrolysis of 100 g p. juliflora pod flour by 250 ml
distilled water at 90 for 30 minutes followed by, 92.4 g/l, 68.1 g/l, and 56.1 g/l with 0.2,
0.4 and 0.8 M sulfuric acid respectively. This shows that treatment of Prosopis juliflora
pod flour releases less glucose with increasing concentrations of sulfuric acid ranging
from 21% with 0.2M to that of 50% reduction with 0.8M acid treated hydrolysate
compared to the glucose concentration of water treated pod flour. NMR analysis of the
fermented hydrolysate gives maximum ethanol concentration of (5% w/v) with water and,
4%, 3 % and 2.5% of ethanol with 0.2, 0.4 M and 0.8 M sulfuric acid hydrolysis at 90oC
for 30 minutes respectively. Treatment with water is an effective way that result the
maximum yield and treatment with 0.8M acid is the least effective. 15 minute hydrolysis
resulted lower ethanol 4%, 2.7%, 2%, and 1.6% with water, 0.2, 0.4 and 0.8M sulfuric
acid respectively. The optimum fermentation time was 24 hour which gives maximum
concentration of ethanol (5%w/v) with water and the concentration decreases slightly
after 24 hours fermentation.