| Summary, etc |
The waste management in Pakistan is plagued by a wide range of public, educational, governmental and economic issues. Bioethanol production is now focusing in the field of bioenergy and to lessen the environmental problems. The Pomegranate fruit wastes are extremely biodegradable that provides an appropriate way out towards both the waste management and energy sources. The study investigated the ethanol production by Response Surface Methodology using central composite design (CCD) was employed to estimate and optimize the conditions by three different dilute acid hydrolysis. In optimization variable factors were acid concentration (X1), hydrolysis temperature (X2) and hydrolysis time (X3) whereas the responses were glucose release, total carbohydrates, weight loss, extractive, hemicelluloses decrease, lignin and cellulose contents. Dilute Sulphuric acid (H2SO4), Nitiric acid (HNO3) and Hydrolchloric acid (HCl) was used for acid hydrolysis. With dilute Sulphuric acid the maximum amount of reducing sugars was 5.63±0.48 released at 5% acid concentration, 100˚C for 30 minutes. The result was not Significant with the F value of 2.67, P value of 0.0798. The value of R squared 0.7276 and adjusted R2 0.4551 also lead to the insignificance of results. After dilute acid hydrolysis, maximum carbohydrates release 15.32±2.69 was observed at 3% acid concentration, 75˚C temperature and 45 minutes. The results were not significant by the statistical analysis showed F as well as P value of 1.05 and 0.4735 correspondingly. The values of R2 (0.5114) and the R2 adjusted (0.0227) showed that the model was not significant. The maximum Hemicellulose decrease was 14.04 at 3% acid concentration, 75˚C temperature for 19.77 minutes. The result was not significant with particular F value of 1.40, P value of 0.3130 and the R2 0.5829. At 1% acid concentration 50˚C hydrolysis temperature and 60 minutes of hydrolysis time xi the maximum lignin contents 35.47±3.23 were observed. The model was not significant with F-value of 1.64 and P-value of 0.2362 showed through statistical analysis. The R squared value of 0.6231 showed that this model was insignificant. The maximum weight loss was (77.33±0.19) recorded at 6.36% acid concentration, 75˚C for 45 minutes. The statistical analysis by ANOVA depicted with F and P values 2.86 and 0.0669 correspondingly. The R2 value was 0.7407 which suggested that the model was not significant. The results with dilute Nitric acid observed the maximum amount of reducing sugars was 6.48±0.96 at 3% acid concentration, 75˚C for 70.23 minutes. The result was Significant with the F-value of 4.72, P value of 0.0151, R squared value of 0.8252 and adjusted R2 0.6505 also counted for the significance of results. Maximum carbohydrates release 25.49±1.03 was observed at 0.36% acid concentration, 75˚C temperature and 45 minutes after dilute acid hydrolysis. The statistical analysis of results was not significant with F as well as P value of 0.30 and 0.9557 correspondingly. The values of R2 0.2315 and R2 adjusted -0.5370 also implied that model was not significant. At 3% acid concentration, 75˚C temperature for 19.77 minutes the Hemicellulose decrease was maximum 20.08±3.46. Result was not significant according to F-value of 1.67, P-value of 0.2295 and the R2 (0.6248) values. Lignin contents were decreased after dilute acid hydrolysis of pomegranate peels. At 5% acid concentration 100˚C hydrolysis temperature and 30 minutes of hydrolysis time the maximum lignin contents 39.57±1.83 were observed. The statistical analysis depicted that model was not significant with F-value of 0.52 and with P-value of 0.8270. The R squared value of 0.3427 also implied that model was insignificant. The weight loss was (51.11±1.24) recorded at 1% acid concentration, 100˚C for 60 minutes. It showed through statistical analysis by ANOVA with F and P values of xii 0.48 and 0.8551 respectively. The 0.3245 R2 value suggested that the model was not significant. According to the results of all tests with dilute Hydrochloric acid the maximum amount of reducing sugars was 5.57±0.74 released at 3% acid concentration, 75˚C for 45 minutes. The result was not significant with the F-value of 0.88, P value of 0.5733, R squared value of 0.0.4684 and adjusted R2 -0.0632 also contributed to the insignificance of results. After dilute acid hydrolysis, maximum carbohydrates release 23.57±0.84 was observed at 1% acid concentration, 50˚C temperature and 30 minutes. Statistical analysis showed that these results were not significant having F and the P value of 1.82 and 0.1930 correspondingly. The values of R2 (0.6453) and R2 adjusted (0.2906) also implied that model was not significant. The hemicellulose decrease was maximum 18.98 at 5% acid concentration, 50˚C temperature for 30 minutes. Result was not significant with respective F-value of 1.16, P-value of 0.4140 and R2 (0.5327) values. Lignin contents were decreased after dilute acid hydrolysis of pomegranate peels. Maximum lignin contents 13.97±1.45 were observed at 3% acid concentration 75˚C hydrolysis temperature and 60 minutes of hydrolysis time. Though statistical analysis showed that model was not significant with F-value of 1.64 and with the P-value of 0.2362. Value of R2 0.6231 also implied that model was insignificant. Weight loss was recorded at (77.33±0.19) 6.36% acid concentration, 75˚C for 45 minutes. It showed through statistical analysis by ANOVA with F and P values 0.56 and 0.7973 correspondingly. The R2 value was 0.3603 which suggested that the model was not significant. Fermentation was done on hydrolyzates prepared after the hydrolysis of Pomegranate peels by three acids that mentioned above. Ethanol yield was 3.37±0.03, xiii 2.88±0.07 and 2.56±0.06 with Nitric, Sulphuric and Hydrochloric acid hydrolyzate respectively. |
