Yacon Flour and Corn Steep Liquor as Substrate for Inulinase and Biomass Production by Kluyveromyces Marxianus NRRL Y-7571

Marcia Luciana Cazetta,Leonardo Amorin Sathler,Jonas Contiero

doi:10.24297/jbt.v4i3.4892

Abstract

Yacon is a perennial plant native of the Andesthat stores inulin-type polyfructans as reserve carbohydrates in its tubers. The enzymes that hydrolyze the inulin Î²-2,1 fructose Â linkages are called inulinases and are much used to produce high fructose syrups (HFS) and ethanol. The present study investigated inulinase and biomass production by Kluyveromyces marxianus NRRL Y-7571 using yacon flour as carbon source and corn steep liquor as nitrogen source by a Central Composite Design (CCD) 22 to carry out experiments and Surface Response Methodology (RSM) to analyze the results. The maximum enzyme production was 36.1 U.ml-1 and biomass production was 8.95 g.l-1 under the condition of 7% yacon flour and 2% corn steep liquor. The crude enzyme partial characterization showed that inulinase had optimal pH at 4.0 and optimal temperature at60Â°C. The enzyme maintained over 90% of its activity for four hours at45Â°C and50Â°C.

Highlights

Inulin-type polyfructans are linear carbohydrates with β(2 1) bonds between the fructose units
Yacon flour was a viable substrate for application in fermentation processes, because of the good inulinase and biomass yields obtained in this work, and because it presented low variability
The results obtained showed that the increase on yacon flour concentration, in the range studied, influenced positively up to the 7.0% limit, and this was the best concentration for production of both biomass and inulinase

Summary

Introduction

Inulin-type polyfructans are linear carbohydrates with β(2 1) bonds between the fructose units They have received a lot of attention recently due to their functional properties, because they improve food texture and fiber content without altering the appearance and flavor of the end product and they have a beneficial effect on the intestinal flora and serum parameters due to their non-digestibility [1,2,3,4]. In the mid-1980s, yacon cultivation started outside the Andes, at first in New Zealand and Japan, from where it spread to other countries, and can be found since the 1990s in Brazil, Paraguay, United States, Slovakia, China, Korea and Taiwan [10] This crop was introduced to Brazil in the early 1990s, in the state of São Paulo [11], but consumption became popular only in the mid 2000s, when this tuber became popularly known as “yacon potato” or “diet potato” [12], especially among people with diabetes and consumers of low calorie foods

Objectives

Methods

Discussion

Conclusion