From Waste Biomass to Cellulosic Ethanol by Separate Hydrolysis and Fermentation (SHF) with Trichoderma viride

Abstract

Advanced biofuels can reduce fossil fuel use and the number of harmful compounds released during combustion, by reducing the use of fossil fuels. Lignocellulosic materials, especially waste biomass, are suitable substrates for the production of advanced biofuels. Among the most expensive steps in the production of ethanol is enzyme-based hydrolysis. Using microorganisms can reduce these costs. This study investigated the effectiveness of hydrolyzing three waste lignocellulosic biomass materials (barley straw, oak shavings, spent grains) into ethanol, after biological pretreatment with Trichoderma viride fungi. The number of fermentable sugars obtained from each substrate was subjected to preliminary study, and the correlation between the temperature and fungal activity in the decomposition of lignocellulosic materials was determined. Ethanol was produced by the separate hydrolysis and fermentation (SHF) method. It was found that not all lignocellulosic biomass is suitable to decomposition and hydrolysis in the presence of T. viride. Regardless of the process temperature, the average enzymatic activity of fungi (activity index) ranged from 1.25 to 1.31. 94 mL of distillate, with a 65% (v/v) ethanol concentration produced by the hydrolysis and fermentation of the sugars released from the barley straw.

A Study on the Valorization of Rice Straw into Different Value-Added Products and Biofuels

“…Te recorded bioethanol yield of 0.38 g/g in the case of bioethanol fermentation by S. cerevisiae ATCC 64712 (Table 10) is comparable to that reported for S. cerevisiae NCIM 3186 in the batch fermentation of TRS produced from alkali-pretreated rice straw saccharifed by T. reesei NCIM-1052 [1]. S. cerevisiae is known to be the most preferable yeast in bioethanol production for its tolerance to elevated ethanol and inhibitors concentrations [21,32].…”

“…Tus, bioethanol is seen as having a substantial market value in many industrial processes as well as a fuel. In addition to the emerging need for the depletion of GHG emissions, air pollution, and mitigation of climate change problems, it is also being considered a global mandate for economy and energy security as well as to resolve the food versus fuel problem [20,21], especially after the Renewable Energy Directive (RED II), which sets a target for the percentage of biofuels used in transport at 14% by 2030 and excludes frst-generation biofuels from the defnition of renewable energy sources [21]. However, the cost of rice straw pretreatment is reported to represent approximately 33% of the overall bioethanol production cost [22].…”

“…Yet, to be a feasible process, applying fungal isolates with sufcient delignifcation and saccharifcation efciencies, besides high capabilities of generating (hemi) cellulolytic enzymes, is mandatory for producing a high yield of fermentable sugars within a short-time solid-state fermentation (SSF) process [25,26]. Te Trichoderma genus strains have been reported to play a crucial role in these processes [21,27]. Te main species involved in that criteria are T. harzianum, T. viride, and T. reseei [28].…”

“…Parametric optimization of rice straw SSF into a sugary solution for bioethanol production using Trichoderma longibrachiatum DSMZ 16517 will be performed in this study. Diferent species of Trichoderma have been used for the pretreatment of rice straw or for (hemi) cellulolytic enzymes production to be utilized for the hydrolysis of lignocellulosic wastes [16,21,[34][35][36][37]. However, to our best knowledge, this is the frst time that whole fungal cells of T. longibrachiatum DSMZ 16517 have been used simultaneously for (hemi) cellulolytic enzymes production besides the hydrolysis and saccharifcation of rice straw.…”

Biotransformation of Lignocellulosic Biomass to Value-Added Bioproducts: Insights into Bio-Saccharification Strategies and Potential Concerns

“…Further, there is a possibility of unwanted fermentations, which may influence the economical sustainability of the bioprocess [50,51,71]. Hawrot-Paw and Staczuk [53] studied the efficiency of enzymatic decomposition of three different waste lignocellulosic biomass sources (oak shavings, barley straw, and spent grains) into ethanol after biological pretreatment with the fungus Trichoderma viride. A pilot study was conducted to determine the yield of fermentable sugars from every substrate.…”