Inulinase Production by Agro-Industrial Residues: Optimization of Pretreatment of Substrates and Production Medium

Abstract

In this work, production of inulinase was studied. Media formulation was optimized by experimental design and response surface techniques, as well as the pretreatment of the agro-industry residues used in the formulation of fermentation medium. Two agro-industry residues were investigated: sugarcane molasses (SCM) and corn steep liquor (CSL). Pretreatment with sulfuric acid was the most effective for clarification of SCM (pH 5.0, 24 h of resting time and final pH 4.0). Clarification of CSL was accomplished with phosphoric acid (pH 3.0, 24 h of resting time and final pH 5.5). A color reduction of approximately 70% was achieved for both substrates. The highest production of inulinase was obtained in a medium containing 100 g l −1 of pretreated SCM, 100 g l −1 of pretreated CSL and 6 g l −1 of Prodex Lac (yeast hydrolysate), yielding 1,139 U ml −1 .

Inulinase production in a batch bioreactor using agroindustrial residues as the substrate: experimental data and modeling

“…Kalil et al [2] and Silva-Santisteban and Maugeri [3] employed submerged fermentation with synthetic media, obtaining maximum productions of 127 and 175 U mL -1 , respectively. Treichel [4] and Sguarezi et al [5] used a medium composed of agroindustrial residues and obtained maximum productions of 1,294 and 1,138 U mL -1 , respectively. In addition, the study of Treichel [4] showed that carrying out an up-stream processing of the substrates made the enzyme purification process viable.…”

“…The results obtained by Treichel [4] and by Sguarezi et al [5] presented an excellent perspective of the scale-up of inulinase production when agroindustrial residues are used as substrates. However, a reliable mathematical model of the process, achieved with limited experimental effort represents an indispensable tool for the scale-up, optimization, control and design of inulinase production.…”

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

“…Furthermore, the complex composition of agroindustrial substrates can cause a negative effect due to the increase in the concentration of some of their constituents [43]. Regarding corn steep liquor, different concentrations are found in the literature, ranging from 0.3% to 20%, or even more [29,45,46,47,48] showing that the response to this substrate depends mainly on the microorganism used and should be adjusted to the metabolic needs of each one.…”

Purification of inulinases by changing the ionic strength of the medium and precipitation with alcohols

“…Bagasse moisture was adjusted to 65 % prior to the innoculation (Mazutti et al 2006). Sugarcane molasses was pre-treated as described by Sguarezi et al 2008.…”