title: A NaBH₄ Coupled Ninhydrin-Based Assay for the Quantification of Protein/Enzymes During the Enzymatic Hydrolysis of Pretreated Lignocellulosic Biomass.
abstract: Accurate protein quantification is necessary in many of the steps during the enzymatic hydrolysis of pretreated lignocellulosic biomass, from the fundamental determination of enzyme kinetics to techno-economic assessments, such as the use of enzyme recycling strategies, evaluation of enzyme costs, and the optimization of various process steps. In the work described here, a modified, more rapid ninhydrin-based protein quantification assay was developed to better quantify enzyme levels in the presence of lignocellulosic biomass derived compounds. The addition of sodium borohydride followed by acid hydrolysis at 130 °C greatly reduced interference from monosaccharides and oligosaccharides and decreased the assay time 6-fold. The modified ninhydrin assay was shown to be more accurate as compared to various traditional colorimetric protein assays when commercial cellulase enzyme mixtures were quantified under typical pretreated lignocellulosic biomass enzymatic hydrolysis conditions. The relatively short assay time and microplate-reading capability of the modified assay indicated that the method could likely be used for high-throughput protein determination.
authors.affiliation: Forest Products Biotechnology/Bioenergy Group, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
authors.forename: Yiu Ki
authors.initials: YK
authors.lastname: Mok
authors.forename: Valdeir
authors.initials: V
authors.lastname: Arantes
authors.forename: Jack N
authors.initials: JN
authors.lastname: Saddler
mesh_terms: D018533:Biomass; D001894:Borohydrides / Q000737:chemistry*; D044602:Cellulases / Q000032:analysis*; D006358:Hot Temperature; D008031:Lignin / Q000737:chemistry*; D009555:Ninhydrin / Q000737:chemistry*
chemical_list: D001894:Borohydrides; C036909:lignocellulose; C025364:sodium borohydride; D008031:Lignin; D044602:Cellulases; D009555:Ninhydrin