Isolation and Screening of Starch-Degrading Microorganisms from Decaying Rootcrops for the Production of Natural Sweetener from Taro (Colocasia esculenta)
Starch-degrading microorganisms from decaying rootcrop tubers were isolated and screened as potential starter cultures in the production of natural sweetener from taro (Colocasia esculenta). A total of 43 microbial isolates were collected from the samples, 24 of which showed starch-degrading potential as exhibited by positive results for iodine test on starch-agar plates. Further test using DNS method showed that molds in general have greater starch-degrading abilities than bacteria and yeasts. The top two isolates with the highest hydrolyzing activity were molds isolated from decaying taro and cassava tubers. The fermentation of cooked taro (VG-9) substrate using the two most promising isolates yielded syrups with TSS values of 11.65 and 13◦ Brix and pH of 5.4 and 4.06. Qualitative tests for sugars showed that the syrups contain reducing sugars, particularly monosaccharides and ketoses most of which are generally referred to as good or prebiotic sugars. Results of the study imply that taro is a potential raw material for natural sweetener production. It is recommended to study combinations of microorganisms to carry out the optimum fermentation process and produce a good quality sugar alternative with maximum health beneﬁts.
Abu, E.A, Ado, S.A. & James, D. B. (2005). Rawstarchdegradingamylaseproduction by mixed culture of Aspergillus niger and Saccharomyces cerevisae grown on sorghum pomace. African Journal of Biotechnology,4,785–790.
Booth, R. H., 1976. Changes in quality of cassava roots during storage. Journal of FoodTechnology. 11,245-264.
Carr, M.E., Black L. T., & Bagby M. O. (1982).Continuous enzymatic liquefaction of starch for sacchariﬁcation. Journal of
Biotechnology and Bioengineering, 14, 2441-2449
Ensymme Consulting for Biotechnology. (2005). Project study for enzymatic productionofHighFructoseSyrup(HFS).
Food and Agriculture Organization [FAO]. (2010). Composition and utilization of taro. Retrieved from http://www.FAO/docrep/005/ac450e/ac450 e07.htm#TopOfPage
Jirarat, T., Sukruedee, A., & Pasawadee, P. (2006). Chemical and physical properties of ﬂour extracted from taro Colocasia esculenta (L.) schott grown in diﬀerent regions of Thailand. Science Asia, 32, 279-284.
Kathiresan, K & Manivannan S. (2006). Alpha-amylase production by Penicillium fellutanum isolated from mangrove rhizospheric soil. African Journal of Biotechnology,5,829-832.
Lowndes,J.,Kawiecki,D.,Pardo,S.,Nguyen, V., Melanson, K. J., Yu, Z., & Rippe, J.M. (2012). The eﬀect of four hypocaloric dietscontainingdiﬀerentlevelsofsucrose or high fructose corn syrup on weight loss andrelatedparameters. NutritionJournal, 11,55.
Pandey A., Selvakumar, P. & Ashakumary L. (2000). GlucoseproductionbyAspergillus niger on rice barn is improved by addition of nitrogen sources. World Journal of Microbiology and Biotechnology, 10, 348-349.
Ray, R.C., Nedunzhiyan, M., & Balagopalan, C. (2000). Microorganisms associated withpostharvestspoilageofyams. Annals ofTropicalResearch. 22:(1&2),31-40.
Silva, R. N., Quintino F.P., Monteiro, V.N., & Asquieri, E.R. (2008). Production of glucoseandfructosesyrupsfromcassava (Manihotesculenta)starchusingenzymes produced by microorganisms isolated from Brazilian cerrado soil. Ciˆencia e TecnologiadeAlimentos,30(1).
Sujaya, I.N., Amachi, S., Yokota, A., Asano, K., & Tomita F. (2001). Identiﬁcation and characterization of lactic acid bacteria in Ragi Tape. World Journal of Microbiology andBiotechnology,17,349-357.
Tan, J. D. & Perez, R. H. (2008). Collection and preservation of antimicrobial producing microorganisms from rootcrops
and other related food and agricultural source. PCARRD Highlights 2008, 106-108.
Teeri, T.T. (1997). Crystalline cellulose degradation: new insight into function of cellobiohydrolases. Trends in Biotechnology,15,160-167.
Wang, N.S. (1998). Starch hydrolysis by amylase [Laboratory Manual]. Department of Chemical & Biomolecular Engineering. UniversityofMaryland.
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