Strain selection and medium optimization for glucoamylase production from industrial potato waste by Aspergillus niger.
BACKGROUND
Glucoamylase is one of the most common enzymes used in the food industry to break down starch into its monomers. Glucoamylase production and its activity are highly dependent on medium composition. Starch is well known as a glucoamylase inducer, and utilization of industrial starchy potato waste is an inexpensive way of improving glucoamylase production. Since glucoamylase production is highly dependent on medium composition, in this study medium optimization for glucoamylase production was considered to enhance glucoamylase activity.


RESULTS
Among the evaluated microbial species, Aspergillus niger van Tieghem was found to be the best glucoamylase-producing fungus. The Plackett-Burman design was used to screen various medium ingredients, and malt extract, FeSO4 .7H2 O and CaCl2 ·2H2 O were found to have significant effects on glucoamylase production. Finally, malt extract, FeSO4 .7H2 O and CaCl2 .2H2 O were optimized by using a central composite design of response surface methodology. The results showed that the optimal medium composition for A. niger van Tieghem was 50 g L(-1) industrial waste potato mash supplemented with 51.82 g L(-1) malt extract, 9.27 g L(-1) CaCl2 ·2H2 O and 0.50 g L(-1) FeSO4 .7H2 O.


CONCLUSIONS
At the end of optimization, glucoamylase activity and glucose production were improved 126% and 98% compared to only industrial waste potato mash basal medium; 274.4 U mL(-1) glucoamylase activity and 41.7 g L(-1) glucose levels were achieved, respectively. © 2015 Society of Chemical Industry.
Department of Agricultural and Biological Engineering, Pennsylvania State University, University Park, PA, 16802, USA.
Gulten
G
Izmirlioglu
Department of Agricultural and Biological Engineering, Pennsylvania State University, University Park, PA, 16802, USA.|Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA.
Ali
A
Demirci
D001234:Aspergillus niger / Q000201:enzymology* / Q000378:metabolism; D019649:Food Industry; D005087:Glucan 1,4-alpha-Glucosidase / Q000378:metabolism*; D007220:Industrial Waste / Q000032:analysis*; D011198:Solanum tuberosum
D007220:Industrial Waste; D005087:Glucan 1,4-alpha-Glucosidase
Aspergillus niger; Plackett-Burman; central composite design; glucoamylase; industrial waste potato mash