Solid–liquid mass transfer coefficients in an ultrasound-irradiated extraction of iota-carrageenan

A 20-kHz intensity ultrasound was used in the extraction of iota-carrageenan from Eucheuma denticulatum seaweed by using water as solvent. In a simplified extraction procedure, the seaweed particle size of 0.7125E-03 m, 1.2E-3 m, and 1.7E-03 m diameter were studied at different ultrasonic amplitude levels, ranging from 2.08E-06 to 6.4E-06 m and the temperatures from 30 to 60 °C. The maximum iota-carrageenan yield obtained was 57.2 %. This study suggested that ultrasound intensity employed reduced the extraction time required and improved the yield of iota-carrageenan by 6 %. The particle diameter variation during the extraction was found to be a linear equation. The solid-liquid mass transfer coefficient was correlated for ultrasound extraction of iota-carrageenan in terms of operating conditions employed in this investigation as kL = 0:0027A0.866Dp -0.533(T)0.133

Palm kernel cake as substrate for ß-Mannanase production by Bacillus subtilis ATCC3366 under submerged and solid state fermentations

Beta-Mannanase activity and growth profile of Bacillus subtilis ATCC3366 during submerged fermentation (SmF) and solid state fermentation (SSF) using palm kernel cake as substrate were examined in this study. After 36 h of fermentation, ß-Mannanase produced by Bacillus subtilis in SmF system was recorded at 8 U/ml, whereas in SSF system was 230 U/g dry PKC. In SmF system, a long lag phase of 28 h were observed before the number of viable cells reached the maximum of 2.08 × 108 CFU/ml at 36 h; whereas in SSF system was 3.75 × 109 CFU/ml at 24 h, with no lag phase observed. Optimum conditions of enzyme activity were also examined. The optimum pH was 7.0, and optimum temperature was 55oC