The main objective of this research was to determine through the response surface methodology conditions of temperature and time of transesterification which could achieve the higher yield and calorific value in the biodiesel obtained. We used the Central Composite Rotational Design type 22 +2*2, including 4 repetitions at the central point. Chicken fat passed through refining processes, esterification and transesterification weather conditions and temperature of each experiment. The best conditions of temperature were between 50 and 70 oC and time of transesterification between 60 and 120 min, we have obtained an average yield of 94.5% and calorific value in the biodiesel obtained from 40.2 MJ / Kg. We conclude that using the temperature of 56 oC and time of 108.4 minutes,biodiesel is obtained with characteristics required by the ASTM D6751-07, EN 14214 and NTP 321.003.2005standards.

The main objective of this research was to determine through the response surface methodology conditions of temperature and time of transesterification which could achieve the higher yield and calorific value in the biodiesel obtained. We used the Central Composite Rotational Design type 22 +2*2, including 4 repetitions at the central point. Chicken fat passed through refining processes, esterification and transesterification weather conditions and temperature of each experiment. The best conditions of temperature were between 50 and 70 oC and time of transesterification between 60 and 120 min, we have obtained an average yield of 94.5% and calorific value in the biodiesel obtained from 40.2 MJ / Kg. We conclude that using the temperature of 56 oC and time of 108.4 minutes,biodiesel is obtained with characteristics required by the ASTM D6751-07, EN 14214 and NTP 321.003.2005standards.

ABSTRACT Freezing (-20 °C, 12h) and alkaline (NaOH 8%) pretreatments were applied individually and combined in rice husk (Oryza sativa L.) before their hydrolysis with cellulase (EC: 3.2.1.4.). The effects on structural modifications, lignin content, cellulose, hemicellulose content and glucose production were evaluated. In addition, the glucose production kinetics were described by using the Peleg model. The homogenous rice husk (1 g) with and without pretreatments was hydrolysed with 150 U of Cellulase in 10 ml of acetate for 60 h (37 °C, pH 5.5, 100 rpm). As results, the SEM images evidenced porous microstructures with less agglomeration generated by all pre-treatments, which were intensified by the combined pretreatment. This pre-treatment allowed to obtain higher cellulose (62.51 ± 0.3 %) content. Besides, the glucose content after pretreatments increased. The Peleg model paramet...