• KSBB Journal
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• v.11 no.3
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• pp.311-316
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• 1996

The effects of polyethylene glycol (PEG) on glucoamylase production in recombinant Saccharomyces cerevisiae were studied. By PEG addition, the cell growth was not affected. However, the glucoamylase production was increased in all range of PEG molecular weights and concentrations. The optimal molecular weight of PEG was 6000 and the optimal concentration was 1g/L. Using these optimals, the extracellular glucoamylase activity was 23% higher in PEG-containing medium than that in medium without PEG.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.13-16
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• 2001

Maltose and soluble starch were used as secondary sources of carbon for glucoamylase production by Aspergillus awamori in solid state fermentation. During batch cultivation, maltose above 2.5%(w/w) repressed glucoamylase production, but, by adding either 2.5% (w/w) maltose or 1.25% (w/w) soluble starch to fed-batch cultivations, glucoamylase activity was increased by 15% and 170% over standard medium, respectively. The data showed that maltose is a weak inducer of glucoamylase production in solid stat fermentation.

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.494-498
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• 1988

The optimum conditions for glucoamylase production, and ethanol productivity of the transformant TSD-14 were investigated as compared with the parental strains. The properties of TSD-14 were comparatively similar to the donor S. diastaticus IFO 1046 as regards the conditions of glucoamylase production and ethanol productivity. The soluble starch was the most effective carbon source for the glucoamylase production. While inorganic nitrogen sources did not prompt cell growth and enzyme production, the organic nitrogen sources generally enhanced both cell growth and glucoamylase production. The metal salts such as FeSO$_4$, MgSO$_4$, MnCl$_2$, and NiSO$_4$were favorable to the enzyme production. And the optium temperature and initial pH for glucoamylase production were 3$0^{\circ}C$ and 5. The transformant TSD-14 produced 8.3%(v/v) ethanol from 15% sucrose medium, 4.8%(v/v) ethanol from 15% soluble starch medium, and 7.5%(v/v) ethanol from 15% liquefied potato starch medium. The corresponding fermentation efficiency were 84% , 45% and 70%, respectively.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.519-523
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• 1989

The effects of carbon, nitrogen sources and culture conditions on glucoamylase production from Aspergillus sp. were investigated. Among tested carbon sources, soluble starch was most effective for the production of the enzyme, and the level of concentration for the optimal enzyme production was found to be 5%. For nitrogen sources, yeast extract was best for the enzyme production, with the level of 0.1%. The enzyme was maximally produced by cultivating the organism at medium of initial pH 6.0, and temperature of 28$^{\circ}C$. Wheat bran was most suitable for the enzyme production from the organism in solid state culture.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.185-195
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• 2015

Glucoamylase is an important industrial enzyme. Glucoamylase production by industrial Aspergillus niger strain featured with two major problems: (i) empirical substrate feeding methods deteriorating the fermentation performance; and (ii) the high raw materials cost limiting the economics of the glucoamylase product with delegated specification. In this study, we first proposed a novel three-stage varied-rate substrate feeding strategy for efficient glucoamylase production in a 5 L bioreactor using the standard feeding medium, by comparing the changing patterns of the important physiological parameters such as DO, OUR, RQ, etc., when using different substrate feeding strategies. With this strategy, the glucoamylase activity and productivity reached higher levels of 11,000 U/ml and 84.6 U/ml/h, respectively. The performance enhancement in this case was beneficial from the following results: DO and OUR could be controlled at the higher levels (30%, 43.83 mmol/l/h), while RQ was maintained at a stable/lower level of 0.60 simultaneously throughout the fed-batch phase. Based on this three-stage varied-rate substrate feeding strategy, we further evaluated the economics of using alternative carbon sources, attempting to reduce the raw materials cost. The results revealed that cornstarch hydrolysate could be considered as the best carbon source to replace the standard and expensive feeding medium. In this case, the production cost of the glucoamylase with delegated specification (5,000 U/ml) could be saved by more than 61% while the product quality be ensured simultaneously. The proposed strategy showed application potential in improving the economics of industrial glucoamylase production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.2
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• pp.188-191
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• 1985

A thermophilic and cellulolytic bacterium, Herpetosiphon geysericola CUM 317 isolated from the compost, produced ${\alpha}-amylase,\;{\beta}-amylase$, and glucoamylase. Mutual relationships on the production of the three amylases were studied by changing the cultivation conditions. ${\alpha}-Amylase$ and glucoamylase were produced highly after 40 hrs on wheat bran medium at $50^{\circ}C$ and after 30 hrs on liquid medium at $40^{\circ}C$, though ${\beta}-amylase$ was produced best at 10 hrs of initial cultivation phase. The production of the amylases was generally repressed by the addition of carbon sources in liquid medium containing polypeptone. ${\alpha}-Amylase$ production was enhanced relatively by the addition of cupric sulfate in the liquid medium, ${\beta}-amylase$ was enhanced by cadmium sulfate, and glucoamylase was enhanced by calcium chloride.

• Korean Journal of Microbiology
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• v.14 no.2
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• pp.49-49
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• 1976

Enzyme activities, such as glucoamylase dextrinogenic amylase, cellulase, acid protase and neutral protease, of Rhizopus isolated from various substrates collected throughout South Korea are measured, and their enzyme activities are surveyed from taxonomical, ecological and physiological viewpoint. Effect of carbon sources and phytohormones on the amylalse production of Rhizopus are also measured. Among the 735 strains of Phizopus isolated, strain number 587 exhibiting most prominent dextrinogenic amylase and netral protease activity is selected as the best strain, and the strain number 673, 108, 329, 165 and 728 are seleted for their predominant cellulase, acid protease, glucoamylase, dextrinogenic amylase and neutral protease activities, respectively. R.acidus and R.nigricans which exhibited relatively higher callulalse activity, showed lower activities for both amylase. R.tritici exhibited higher protease activity. The relations between activities and various substrates of wild strains are not outstnading difference, although the strains isolated from inland region exhibited more or less higher amylase and cellulase activities, than those of coast region, generally. Lactose and dextrin are most effective carbon sources for glucoamylase and dextrinogenic amylase production of the Rhizopus niveus, respectively. Although all phytohormones tested are effective for production of amylase by the Rhizopus strains, except nicotinamide for glucoamylase production, biotin and ascorbate are most effective for dextrinogenic amylase and glucoamylase production, respectively.

• Korean Journal of Microbiology
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• v.14 no.2
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• pp.47-56
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• 1976

Enzyme activities, such as glucoamylase dextrinogenic amylase, cellulase, acid protase and neutral protease, of Rhizopus isolated from various substrates collected throughout South Korea are measured, and their enzyme activities are surveyed from taxonomical, ecological and physiological viewpoint. Effect of carbon sources and phytohormones on the amylalse production of Rhizopus are also measured. Among the 735 strains of Phizopus isolated, strain number 587 exhibiting most prominent dextrinogenic amylase and netral protease activity is selected as the best strain, and the strain number 673, 108, 329, 165 and 728 are seleted for their predominant cellulase, acid protease, glucoamylase, dextrinogenic amylase and neutral protease activities, respectively. R.acidus and R.nigricans which exhibited relatively higher callulalse activity, showed lower activities for both amylase. R.tritici exhibited higher protease activity. The relations between activities and various substrates of wild strains are not outstnading difference, although the strains isolated from inland region exhibited more or less higher amylase and cellulase activities, than those of coast region, generally. Lactose and dextrin are most effective carbon sources for glucoamylase and dextrinogenic amylase production of the Rhizopus niveus, respectively. Although all phytohormones tested are effective for production of amylase by the Rhizopus strains, except nicotinamide for glucoamylase production, biotin and ascorbate are most effective for dextrinogenic amylase and glucoamylase production, respectively.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.875-880
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• 2000

The production of glucoamylase and exopolygalacturonase from Cryptococcus laurentii Y-23 were investigated with the inducible substrates and mineral salts. Soluble starch induced only glucoamylase wherease pectin induced exopolygalacturonase as well as glucoamylase, and glucose did not induce glucoamylase whereas pectic acid induced a little amount of exopolygalacturonase. At the productions of two enzymes by inducible substrates for the 5 day-cultivation, the yeasts started log phase around 12 hours and mostly reached stationary phase around 36 hours. The best productivity of glucoamylase was observed with addition of soluble starch in the cultivation for 72 to 86 hours, and the high productivity of exopolygalacturonase was done by addition of both pectin and soluble starch in the cultivation for more than 72 hours. Without ammonium sulfate in the medium, however, cultural pH was so increased gradually that production of both enzymes were decreased and delayed as well. $Mn^{2+}$ increased both productivities of glucoamylase and exopolygalacturonase with 21% and 18%, respectively.

• Korean Journal of Microbiology
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• v.18 no.4
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• pp.161-171
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• 1980

A mutant strain having increased productivity of both enzymes, protease and amylase, was obtained from A. flavus KU 153, isolatd from South Korea for its high protease production by successive ultra-violet light irradiation, Two glucoamylases from the mutant strain selected were purified from wheat branculture by successive salting out, followed by dialysis and column chromatography, and their characteristics were compared with those of the wild strain. Glucoamylase production of the mutant selected was increased about 3.3 times compared with the wild strain, and 2.1 times compared with the parental strain, ${\alpha}-amylase$ activity of the mutant selected was about 2 times hugher than that of the wild strain or the parental strain. Protease and cellulase productivities of the muant selected were all alike compared with those of the highly proteolytic mutant, the parental strain. Therefore, it was considered that the back mutation on the protease production did not occurred in the formation process of the glucoamylase producing mutant. Total activities of glucoamylase I and II from the mutant selected were 2.86 and 3.65 times higher compared with those from the wild strain, respectively. Considering the optimal pH-thermal stability and Km-Vmax value of glucoamylase I and II from both strains, wild and mutant, it was deduced that the characteristics of glucoamylase I and II from the wild strain did not altered during the mutation process. Therefore, it was concluded that the selected mutant did not induce the formation of another glucoamylase isozyme, or the changes in the characteristics of the glucoamylase, but induce the productivity of the same glucoamylase I and II by the action of regulatory gene.