Optimization of alkaline amylase production by thermophilic Bacillus stearothermophilus AN 002

Abstract

Bacillus srearothermophilus AN 002 secreted thermostable alkaline amylase into a liquid growth medium containing 2 g/l starch. Amylase activity was highest at early stationary phase of growth. Among the various carbohydrates tested maximum amylase production was obtained with starch. When starch was replaced by other carbon sources, amylase production was reduced. Peptone and corn steep liquor (CSL) were the ideal nitrogen sources for amylase production by this strain. Of the phosphate sources tested, (NH,),HPO, showed best restults. Amylase production was highest in a laboratory fermenter at a initial p H of 6.5 and a t a constant p H of 7.0. The optimum aeration and agitation for amylase production were 0.66 v/v/m and 400 rev/min, respectively. Maximum growth was obtained at 55 "C and maximum amylase was produced at 50 "C. The amylase was found to be stable between pH 6.0 to 11.0.The media composition and cultural conditions play key roles on the production of thermostable a-amylase by Bacillus spp. (Chandra et al. 1980, SRIVASTAVA andBARUAH 1986). Optimization of cultural condition for maximum production of emzyme is obligatory for each strain. COLEMAN and GRANT (1966) reported that glucose and glycerol added to growing culture of B. amyloliquefaciens did not cause catabolic repression on amylase synthesis. SAITO and YAMAMOTO (1975), MEERS (1972) and CHANURA et al. (1980) observed that ?-amylase production was repressed by low molecular weight metabolizable sugars. The stimulatory effect of complex nitrogen source is attributed to their content of certain growth factors or enzyme inducers, suitable combination of amino acids, trace elements and vitamins. High amylase activities of Bacilluspolymyxa were obtained in media containing starch and peptone (GRIFFIN and FOGARTY 1973). The complex nitrogen sources eg. peptone or corn steep liquor (CSL), strongly repressed the synthesis of amylolytic enzymes in Trichoderma viride (SCHELLART et al. 1976). Casein, ground nut protein and CSL served as good nitrogen sources for the production of a-amylase from Aspergillus niger (RAMACHAN-DRAN er al. 1979). Phosphates are known to be effective stimulators for amylase production (FUKUMOTO et al. 1957).These observations obviously lead one to investigate about the nutritional requirements of different strains for the production of a-amylase. BEZBARUAH et al. (1991) reported earlier that a strain of B. stearothermophilus AN 002 produces thermostable a-amylase which has an extremely broad pH range, 6 to 11 (optimum pH 9.5) and temperature range 55 to 85 "C (optimum at 80 'C) for amylase activity. In this communication an ideal cultural condition for the production of a-amylase by B. s t~~r~t~e r~o p h i~t~~~ AN 002 is reported. Materials and methodsMicroorganism and culture conditions: Isolation of B. stearothermophilus AN 002 and its maintenance have been described earlier (BEZBARUAH et a/. 1991). Unless otherwise stated the aniylase production medium was of the following composition (g/l): Starch (BDH), 2; peptone (DIFCO), 5...

Optimization of the growth of and α-amylase production by Bacillus subtilis IP 5832 in shake flask and laboratory fermenter batch cultures

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“…5 Optimization of cultural conditions is important for maximum production of microbial strains. 6 In this regard, appropriate media components and suitable conditions must be attained for optimal production of the required products. Bacillus species and other forms of microorganisms grow at different rates with specificity to different substrates in the culture medium.…”

Optimization of Alkaline Α-Amylase Production by Thermophilic Bacillus Subtilis

“…The basal medium for α-amylase production contained (g/l): peptone, 10.0 g; yeast extract , 0.2 g; soluble starch, 10.0 g; NaCl , 2.0 g; MgSO 4 .7H 2 O, 0.5 g; KH 2 PO 4 , 3.0 g and CaCl 2 , 0.5 g. The pH was adjusted to 8.0. Fifty ml of basal medium were inoculated at 10% (v/v) level and incubated at 45°C on a rotary shaker for 48h.…”

Protease and xylanase activities and thermophilic populations as potential process monitoring tools during thermophilic aerobic digestion

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