Saccharification and Fermentation of Cellulolytic Agricultural Biomass to Bioethanol using Locally Isolated Aspergillus niger S48 and Kluyveromyces sp. Y2, respectively

Abstract

Due to increase in demand for energy as a result of human population explosion, industrialization and environmental hazards posed by fossil fuels, there is a need to source for alternative energy sources that are cheaper and environmental friendly. Three different lignocellulosic biomasses were studied for their suitability for bioethanol production. Fungi and yeasts were isolated using serial dilution and spread plate methods. Identification of both fungi and yeasts was done using their cultural and microscopy characteristics. Saccharification of the pre-treated biomass was done with both crude cellulase and mycelia inoculant. Bioethanol was produced using batch culture fermentation. Ethanol produced was detected using spectrometric method and quantified using High Performance Liquid Chromatography (HPLC). The effects of substrate concentration, pH and temperature on ethanol yield were optimized. Fifty fungal isolates were obtained from soil collected. Six yeasts, all Kluyveromyces species fermented three sugars to ethanol with isolate Kluyveromyces sp.Y2 having the shortest time. It was selected for fermentation. Aspergillus niger S48 had highest cellulase activity measured in a zone of hydrolysis of 26.0 mm. It had the highest glucanase activity, endoglucanase (0.462 U/mL) and exoglucanase (0.431 U/mL). The outcome of this study indicated that crude cellulase produced by Aspergillus niger S48 hydrolyzed the pre-treated rice chaff with 1.07 mg/mL of fermentable sugars higher than 0.87 mg/mL when the mycelia of the fungus was inoculated to pretreated rice chaff for hydrolysis. Ethanol was optimally produced at 12 % substrate concentration using rice chaff, at a temperature of 35 °C and pH 5.0.

Investigation of Carbon Footprints of Three Desalination Technologies: Reverse Osmosis (RO), Multi-Stage Flash Distillation (MSF) and Multi-Effect Distillation (MED)

“…Among the causes of global disasters, climate change is the leading cause of natural disasters, extreme weather, food shortages, and ecosystem collapse [1][2][3]. A significant cause of climate change is an increase in the surface temperature of the earth (global warming), which is caused by an increase in greenhouse gas (GHG) concentrations.…”

Effects of two kinds of Bacillus on flavour formation of Baijiu solid‐state fermentation with pure mixed bacteria

“…The key to the success of Baijiu brewing has been to convert macromolecular sugars in raw materials into ethanol (Yin et al ., 2020). Saccharomyces cerevisiae generated high ethanol production, and Aspergillus niger , as an important fungal strain in the production of Maotai‐flavoured Baijiu, produced excellent liquefaction and saccharification (Adeyemo et al ., 2021; Hong et al ., 2021). Actinomycetes, as the most popular Baijiu microorganism, were of great significance to the formation of Baijiu flavour (Fan et al ., 2020).…”

Screening of Fungi From the Trichocomaceae Family (Aspergilli and Penicillia) in Production of Hexose Sugars From Agro-Waste

“…Enzymes are biological catalysts that are very specific in nature [18], therefore employing them as catalysts for the hydrolysis of agro-waste to C6-sugars is seen as a green process that requires relatively milder reaction conditions. The use of aspergillus fungi biocatalyst belonging to the trichocomaceae family for the transformation of various biomass feedstock to different bio-based chemicals have been widely reported in literature especially aspergillus niger [19][20][21][22][23]. However, most of these processes usually involve the pretreatment of samples with the undesired mineral acids.…”