کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6450372 | 1415994 | 2017 | 12 صفحه PDF | دانلود رایگان |
- Fermentations involved 27Â kg of wheat bran and 3Â kg of sugarcane bagasse.
- Three regimes were compared: 1 (10Â h), 3 (8-10-12Â h) and 5 (8-10-12-14-16Â h) agitations.
- The best regime was three agitation events, with harvesting at 20Â h.
- Substrate agglomeration was avoided and the bed temperature was well controlled.
- This gave uniform pectinase levels: 22Â UÂ gâ1, with a sample standard error of 2Â UÂ gâ1.
Solid-state fermentation could be used to produce low-cost pectinases that could then be used to saccharify pectin in citrus waste biorefineries. Recently, we produced pectinases in a pilot-scale packed-bed bioreactor, growing Aspergillus niger on a substrate mixture consisting of 27Â kg of wheat bran and 3Â kg of sugarcane bagasse (dry mass). However, the agglomeration of particles and shrinkage of the bed created preferential flow paths, leading to overheating within the bed and poor uniformity of pectinase levels at the end of the fermentation. In the current work, we used intermittent agitation as a strategy to minimize agglomeration, comparing one agitation (10Â h), three agitations (at 8, 10 and 12Â h) and five agitations (every 2Â h from 8 to 16Â h). The pectinase activity in the bed was uniform after agitation, but poor uniformity occurred when the bed was left unmixed for more than 10Â h. The best regime was that with three agitations: For 15 samples removed from different vertical and horizontal positions of the bed at 20Â h, the average pectinase activity was 22Â UÂ gâ1, with a sample standard deviation of 2Â UÂ gâ1. We conclude that the use of intermittently-mixed packed-bed bioreactors is a promising strategy for producing pectinases in solid-state fermentation.
228
Journal: Biochemical Engineering Journal - Volume 121, 15 May 2017, Pages 1-12