scholarly journals A Review of Potential of Lignocellulosic Biomass for Bioethanol Production in Kenya

Author(s):  
John Odhiambo Otieno ◽  
Fredrick Onyango Ogutu

Lignocellulosic biomass is the earth’s most abundant and renewable resource, and, lignin is its strongest component. The lignocellulosic biomass has a potential to produce bioethanol for both domestic and industrial use. The presence of lignin in the biomass, however, hinders the processing and production of bioethanol from the biomass. Hence, to enhance the chances of bioethanol production from the lignocellulosic biomass, lignin has to be pre-treated. The pre-treatment process efficiently separates the interlinked complex components. During the pre-treatment process, the strong lignin component that is highly resistant and a major barrier to solubilization is broken down by hydrolysis of cellulose and hemicellulose. Pre-treatment of lignocellulosic biomass is therefore, necessary to make it more susceptible to microorganisms, enzymes, and pathogens. The initial pre-treatment approaches include physical, physicochemical, and biological methods. The major drawback of this pre-treatment process is its cost implications, as it’s very costly. Studies suggest that even though it’s a costly affair, the pre-treatment methods, however, have a significant impact on the efficient production of ethanol from biomass. Situation Analysis: Bioethanol production from lignocellulosic biomass has mostly been undertaken in Brazil, USA, China, and India. In Kenya, however, little research on bioethanol production from lignocellulosic biomass has been done and adopted. The present review paper seeks to outlay the benefits of bioethanol production from lignocellulosic biomass, the composition of lignocellulosic biomass, its properties, different pre-treatment methods alongside advantages, and, disadvantages, and challenges encountered during bioethanol production. This review eventually will be of great assistance to researchers while developing bioethanol from different lignocellulosic biomass. Research, technology adaption/adaptation, and policy targeted at growing bioethanol industry, could enable Kenya to grow her bioethanol industry.

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2074 ◽  
Author(s):  
Merlin Raud ◽  
Vahur Rooni ◽  
Timo Kikas

As the pretreatment process is the most expensive and energy-consuming step in the overall second generation bioethanol production process, it is vital that it is studied and optimized in order to be able to develop the most efficient production process. The aim of this paper was to investigate chemical and physical changes in biomass during the process of applying the explosive decompression pretreatment method using two different gases—N2 and synthetic flue gas. The explosive decompression method is economically and environmentally attractive since no chemicals are used—rather it is pressure that is applied—and water is used to break down the biomass structure. Both pre-treatment methods were used at different temperatures. To be able to compare the effects of the pretreatment, samples from different process steps were gathered together and analysed. The results were used to assess the efficiency of the pretreatment, the chemical and physical changes in the biomass and, finally, the mass balances were compiled for the process during the different process steps of bioethanol production. The results showed that both pre-treatment methods are effective in hemicellulose dissolution, while the cellulose content decreases to a smaller degree. The high glucose and ethanol yields were gained with both explosive pretreatment methods at 175 °C (15.2–16.0 g glucose and 5.6–9.0 g ethanol per 100 g of dry biomass, respectively).


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Anita Ejiro Nwaefuna ◽  
Karl Rumbold ◽  
Teun Boekhout ◽  
Nerve Zhou

AbstractBioethanol from abundant and inexpensive agricultural and industrial wastes possesses the potential to reduce greenhouse gas emissions. Bioethanol as renewable fuel addresses elevated production costs, as well as food security concerns. Although technical advancements in simultaneous saccharification and fermentation have reduced the cost of production, one major drawback of this technology is that the pre-treatment process creates environmental stressors inhibitory to fermentative yeasts subsequently reducing bioethanol productivity. Robust fermentative yeasts with extreme stress tolerance remain limited. This review presents the potential of dung beetles from pristine and unexplored environments as an attractive source of extremophilic bioethanolic yeasts. Dung beetles survive on a recalcitrant lignocellulose-rich diet suggesting the presence of symbiotic yeasts with a cellulolytic potential. Dung beetles inhabiting extreme stress environments have the potential to harbour yeasts with the ability to withstand inhibitory environmental stresses typically associated with bioethanol production. The review further discusses established methods used to isolate bioethanolic yeasts, from dung beetles.


2021 ◽  
Vol 13 (2) ◽  
pp. 643-655
Author(s):  
A. Thomas ◽  
M. Laxmi ◽  
A. Benny

With decades of studies on cellulose bioconversion, cellulases have been playing an important role in producing fermentable sugars from lignocellulosic biomass. Copious microorganisms that are able to degrade cellulose have been isolated and identified. The present study has been undertaken to isolate and screen the cellulase producing bacteria from soils of agrowaste field. Cellulase production has been qualitatively analyzed in carboxy methylcellulose (CMC) agar medium after congo red staining and NaCl treatment by interpretation with zones around the potent colonies. Out of the seven isolates, only two showed cellulase production. The morphogical and molecular characterization revealed its identity as Escherichia coli and Staphylococcus aureus. The potential of organisms for bioethanol production has been investigated using two substrates, namely, paper and leaves by subjecting with a pre-treatment process using acid hydrolysis to remove lignin which acts as physical barrier to cellulolytic enzymes. Ethanolic fermentation was done using Saccharomyces cerevisiae for 24-48 h and then the bioethanol produced was qualitatively proved by iodoform assay. These finding proves that ethanol can be made from the agricultural waste and the process is recommended as a means of generating wealth from waste.


2015 ◽  
Vol 8 (2) ◽  
pp. 1-17 ◽  
Author(s):  
Shivani Bhagwat ◽  
Supriya Ratnaparkhe ◽  
Anil Kumar

2018 ◽  
Vol 156 ◽  
pp. 03022 ◽  
Author(s):  
Diah Meilany ◽  
MTAP Kresnowati ◽  
Tjandra Setiadi

Biorefinery industry used lignocellulosic biomass as the raw material. Oil Palm Empty Fruit Bunch (OPEFB) is one of Indonesian potential lignocellulosic biomass, which consists of hemicellulose with xylan as the main component. Xylitol production via fermentation could use this xylan since it can be converted into xylose. However, the structure of OPEFB is such that hemicellulose is protected in a way that will hinder hydrolysis enzyme to access it. Considering that hemicellulose is more susceptible to heat than cellulose, a hydrothermal process was applied to pre-treat OPEFB before it was hydrolyzed enzymatically. The aim of the research is to map the effect of temperature, solid loading and time of pre-treatment process to obtain and recover as much as possible accessible hemicellulose from OPEFB. The results showed that temperature gave more significant effect than time and solid loading for glucose recovery of OPEFB residues. While xylose recovery varies greatly with temperature, but solid loading and time gave less significant effect.


Author(s):  
K A Ghazali ◽  
S F Salleh ◽  
T M I Riayatsyah ◽  
H B Aditiya ◽  
T M I Mahlia

2018 ◽  
Vol 40 (4) ◽  
pp. 50-57
Author(s):  
А.A. Dolinskyi ◽  
O. M. Obodovych ◽  
V.V. Sydorenko

The paper presents an overview of bioetanol production technologies. It is noted that world fuel ethanol production in 2017 amounted to more than 27,000 million gallons (80 million tons). Eight countries, namely the USA, Brazil, the EU, China, Canada, Thailand, Argentina, India, together produce about 98% of bioethanol. In Ukraine, the volume of bioethanol production by alcoholic factories in recent years has been gradually increasing and amounted to 2,992.8 ths. dal in 2017. The production of ethanol as an additive to gasoline, with regard to the raw materials used, as well as the corresponding technologies, is historically divided into three generations. The first generation of biofuels produced from food crops rich in sugar or starch is currently dominant. Production of advanced biofuels from non-food crop feedstocks is limited. Output is anticipated to remain modest in the short term, as progress is needed to improve technology readiness. The main stages of bioethanol production from lignocellulosic raw materials are pre-treatment, enzymatic hydrolysis and fermentation. The pre-treatment process aims to reduce of sizes of raw material particles, provision of the components exposure (hemicellulose, cellulose, starch), provision of better access for the enzymes (in fermentative hydrolysis) to the surface of raw materials, and reduction of crystallinity degree of the cellulose matrix. The pre-treatment process is a major cost component of the overall process. The pre-treatment process is highly recommended as it gives subsequent or direct yield of the fermentable sugars, prevents premature degradation of the yielded sugars, prevents inhibitors formation prior hydrolysis and fermentation, lowers the processing cost, and lowers the demand of conventional energy in general. From the perspective of efficiency, promising methods of pre-treatment of lignocellulosic raw materials to hydrolysis are combined methods combining mechanical, chemical and physical mechanisms of influence on raw materials. One method that combines several physical effects on a treated substance is the discrete-pulsed energy input (DPIE) method. The DPIE method can be applied in the pre- treatment of lignocellulosic raw material in the technology bioethanol production for intensifying the process and reducing energy consumption. Ref. 15, Fig. 2.


2021 ◽  
pp. 129038
Author(s):  
Nurul Suhada Ab Rasid ◽  
Amnani Shamjuddin ◽  
Athran Zuhail Abdul Rahman ◽  
Nor Aishah Saidina Amin

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