The Process of Xylanase Production from Bacillus pumilus RXAIII-5

Abstract

The optimum conditions for the growth of Bacillus pumilus RXAIII-5 (a potential xylanase producer) were sought, these included temperature, pH, aeration, and agitation of the culture batch. Afterwards a mathematical model based on the parameter of cultivation kinetics was formulated. At the same time, the rheology of the fluid used for bacterial cultivation in a bioreactor was studied. The data obtained was used for estimating the 'scaling up' of enzyme production. The results of the study indicate that the optimum condition for processing in 50 ml Erlenmeyer flask are used temperature of 35 o C (308 o K), pH 7, and an agitation rate of 140 rpm. The highest xylanase activity and its specific activity are 297.132 U.ml -1 and 655.32 U.g -1 protein, respectively. Subsequent experiments in a bioreactor using all of the experiment parameters mentioned above, except for the agitation rate, shows that the results are as follows. The highest specific growth was at 0.082 hour -1 at an aeration and agitation rate of 0.5 vvm and 150 rpm, respectively. Based on the data of the cultivation kinetics, the optimum conditions for the fermentation in Biostat 2L-bioreactor is 1 vvm and 200 rpm of aeration and agitation, respectively. The efficiency of substrate (Yp/s) and of cell biomass (Y p/x ) to produce xylanase is 50.744 U.g -1 and 43.906 U.g -1 , respectively. The efficiency of substrate to cell production (Y x/s ) is 1.178g.g -1 . The liquid cultivation-medium has non-Newtonian properties. Based on a mathematical model it is found that the consistency index (k constant) and index of liquid behavior (n value) are 0.179 g.cm -1 .second -1 and 0.3212, respectively. Becouse the value of 0<n<1 and the constant k>0, the culture liquid is categorized as pseudo plastic one. The Rheynold number (NRe) is 6.9 x 10 3 which indicates it has turbulent characteristics. From a calculation it is found that the power required to run a suitably sized impeller is 0.228 HP (Horse Power) and the power consumption per unit volume is 0.2265 HP.m -3 . All these values were used for scaling up xylanase production in the bioreactor.

Batch Submerged Fermentation in Shake Flask Culture and Bioreactor: Influence of Different Agricultural Residuals as the Substrate on the Optimization of Xylanase Production by Bacillus subtilis and Aspergillus brasiliensis

“…This happen when the initial medium composition and optimum growth condition promoted the cell count that directly affected the xylanase activity. As indicated by Richana N, et al [38], when the efficiency of substrates consumption increased, the efficiency of enzymes production by cell biomass also increased. As the batch submerged fermentation proceeded, the cells reached the stationary phase in the shake flask culture, the nutrients including carbon source would gradually became inadequate to support the rapid cell reproduction and eventually started to deplete rapidly.…”

Characteristics of Biochars from Plant Biomass Wastes at Low-Temperature Pyrolysis

“…To illustrate, the gross national product of rice, corn, palm oil, and cane sugar in Indonesia in 2013 were 71; 18; 26; and 2 million tons year -1 , respectively (BPS, 2017). These can be correlated with the reported production wastes likewise generated, that is, 30-40% rice husk (Patabang, 2012), 40-50% corn cob (Richana et al, 2007), 40-45% empty oil palm fruit bunch (Gurning, Tetuko, & Sebayang, 2013), and 30% bagasse (Mirwan, 2005) out of the respective gross harvest yields of the said crops. Unless effectively and efficiently utilized, these agricultural wastes would potentially just go down the drain and even pose a serious environmental hazard.…”

The Potency of Corn (Zea Mays) Cob Waste as a Prebiotic Candidate to Support the Growth of Bifidobacterium longum: a Preliminary Study

“…Currently, corn cob is being used for bio-ethanol, animal feeding, fertilizer, feedstock for cellulosic ethanol, and as base product for various industries (Pennington, 2020). Corn cob is a lignocellulose material with 12.4% of xylan, the highest among agriculture wastes (Richana et al, 2007). Xylan can be hydrolysed to produce xylose and further fermentation will produce xylitol (Mardawati et al, 2018;Fairus et al, 2016).…”