On the production cost of lignocellulose‐degrading enzymes

Abstract

Lignocellulose is the most abundant renewable material on Earth and the primary component of agricultural wastes such as sugarcane bagasse and wheat straw. It consists of a composite material made of cellulose, hemicellulose, and lignin. Cellulose and hemicellulose can be broken down into monomers by a set of appropriate enzymes, and the resulting monomers may be used to produce a variety of fuels or chemicals through either biological or chemical routes. However, the high production cost of these lignocellulose‐degrading enzymes remains a major challenge for the use of lignocellulosic biomass as raw material. In this context, this article reviews techno‐economic analyses concerning the production of cellulases and other lignocellulose‐degrading enzymes published over the last two decades. The major characteristics of each enzyme production process are described, underscoring the similarities and differences across the various process designs. Moreover, the enzyme production costs derived from these process designs and their composition in terms of raw materials, capital‐related factors, utilities, labor costs, etc., are compared. First, this analysis reveals that most techno‐economic evaluations in the literature address either cellulase production by submerged culture with Trichoderma reesei or enzyme production by solid‐state culture with filamentous fungi. Second, this analysis shows wide cost variations across process designs but it indicates that raw materials and capital‐related costs are generally the main drivers of the enzyme production cost. Furthermore, this assessment corroborates the importance of process parameters, such as product yield, production titer, and volumetric productivity, in the process economics of enzyme production. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

Current perspective on production and applications of microbial cellulases: a review

“…Ferreira et al (2021) analyzed the production cost of lignocellulose degrading enzymes and reveals that the most preferred organism and methods for lignocellulolytic enzyme productions are Trichoderma reesei (Teleomorph Hypocrea jecorina) and filamentous fungi using Fig. 4 Techno-economic aspect of cellulase production: a generic flowsheet of a cellulase production process with filamentous fungi [adapted with permission (Ferreira et al 2021)]. b Cost contributors of enzyme production in (Swedish kronor) SEK/L ethanol.…”

Bioreactor and Bioprocess Design Issues in Enzymatic Hydrolysis of Lignocellulosic Biomass

“…However, the cost of cellulases is one of the main economic bottlenecks for the industrial scale implementation of lignocellulosic biorefinery [25]. Techno-economic analysis of the production cost of cellulase in the literature gives a quite broad range for the unit cost of cellulase: 3-300 Euro/kg [11,12,[26][27][28][29][30][31][32]. Many of these analyses rely on using glucose as carbon source for the fermentative production of cellulase.…”

“…Many of these analyses rely on using glucose as carbon source for the fermentative production of cellulase. Realistic cellulase cost ranges between 3 and 8 Euro/kg [12,29]. Assuming an enzyme loading per unit of cellulose ranging between 10 and 30 mg/g [9], cellulose contents within the biomass of between 30 and 70%, and efficiency of hydrolysis ranging between 70% and 90%, the final impact of the cellulase per sugar produced is 0.09 ± 0.05 Euro/kg, which results in 0.18 Euro/kg of lignocellulose biomass.…”

“…For example, in the case of ethanol production from lignocellulose biomass, this counts for 0.05-1 Euro/kg of the total production cost [11]. Thus, the operation asks for a careful design of the bioreactor and an efficient use of enzymes as biocatalysts [8,12]. The main open issues revealed by the current state of the art are: (i) the balance between high sugar yield (favored at diluted biomass working conditions-about 5%wt) and high sugar concentrations in the liquid hydrolysate (favored in bioreactors working at high solid loading >15%wt); (ii) the variability of biomass composition, typically affecting second generation biorefinery, based on the valorization of lignocellulosic wastes that avoids a comprehensive assessment of heterogeneous hydrolysis kinetics; and (iii) the continuous use of the enzymes and difficult recycling hindered by the nature of the process involving the adsorption of the biocatalyst on the solid substrate.…”

Fermentative Production of Lasiodiplodan by Lasiodiplodia theobromae CCT3966 from Pretreated Sugarcane Straw

“…In this regard, the tremendous biological characteristics of lasiodiplodan such as anti-proliferative effect on breast cancer cells, hypoglycemic function, and antioxidant activities have made it an attractive biopolymer for commercial applications [5,6]. Generally, the production costs of the fermentative products highly depend on the fermentation substrates, mainly carbon source, as the use of raw materials such as lignocellulosic biomass and agro-industrial residues decrease the manufacturing costs [7].…”