scholarly journals Bioethanolic yeasts from dung beetles: tapping the potential of extremophilic yeasts for improvement of lignocellulolytic feedstock fermentation

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.

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.


2018 ◽  
Vol 30 (3) ◽  
pp. 462-480 ◽  
Author(s):  
Valerii Havrysh ◽  
Vitalii Nitsenko ◽  
Yuriy Bilan ◽  
Dalia Streimikiene

Since the 1990s, the volume of biogas produced in the world has been increasing. Biomethane (upgraded biogas) is a more versatile renewable fuel. Biogas transportation from production sites to upgrading facilities induces a scale advantage and an efficiency increase. Therefore, exploration of costs and energy use of biogas transportation using dedicated infrastructure is needed. A mathematical model to determine the optimum location for a certain biogas upgrading plant has been presented. It was developed to describe a local biogas grid that is used to collect biogas from several digesters and to deliver it to a central upgrading point. The model minimizes operational and maintenance costs per volumetric unit of biogas. The results indicate that cooperation between biogas producers in collecting biogas by means of a star layout reduces the cost of biomethane production (investment costs by 22.4–24.8% and operating and maintenance costs by 1.7–10.9%) relative to using a decentralized method. Merging smaller digesters into a smaller number of larger biogas upgrading plants reduces the biomethane production costs for the same biogas volume source.


Author(s):  
SAFITRI NURHIDAYATI ◽  
RIZKI AMELYA SYAM

This study aims to analyze whether the difference that occurs in the cost of raw materials, direct labor, and factory overhead costs between the standard costs and the actual costs in PLTU LATI is a difference that is favorable or unfavorable. Data collection techniques with field research and library research. The analytical tool used is the analysis of the difference in raw material costs, the difference in direct labor costs and the difference in factory overhead costs. The hypothesis in this study is that the difference allegedly occurs in the cost of raw materials, direct labor costs, and factory overhead costs at PT Indo Pusaka Berau Tanjung Redeb is a favorable difference. The results showed that the difference in the cost of producing MWh electricity at PT Indo Pusaka Berau Tanjung Redeb in 2018, namely the difference in the price of raw material costs Rp. 548,029.80, - is favorable, the difference in quantity of raw materials is Rp. 957,216,602, - is (favorable) , the difference in direct labor costs Rp 2,602,642,084, - is (unfavorable), and the difference in factory overhead costs Rp 8,807,051,422, - is (favorable) This shows that the difference in the overall production cost budget is favorable or profitable. This beneficial difference shows that the company is really able to reduce production costs optimally in 2018.  


1986 ◽  
Vol 18 (9) ◽  
pp. 163-173
Author(s):  
R. Boll ◽  
R. Kayser

The Braunschweig wastewater land treatment system as the largest in Western Germany serves a population of about 270.000 and has an annual flow of around 22 Mio m3. The whole treatment process consists of three main components : a pre-treatment plant as an activated sludge process, a sprinkler irrigation area of 3.000 ha of farmland and an old sewage farm of 200 ha with surface flooding. This paper briefly summarizes the experiences with management and operation of the system, the treatment results with reference to environmental impact, development of agriculture and some financial aspects.


1994 ◽  
Vol 30 (10) ◽  
pp. 97-106 ◽  
Author(s):  
Cheng-Fang Lin ◽  
Oliver J. Hao ◽  
Fu-Tien Jeng

The main purpose of this study was to establish an inhibitory database using the Microtox assay for different wastes. The waste samples included 19 pretreated industrial wastes from two different industrial parks, 11 other industrial wastes outside industrial parks, and different treatment process effluents. The following is a brief summary of the findings from this study: (1) COD and BOD had a close relationship among different wastes; (2) Microtox data did not correlate with the conventional parameters of BOD, COD and SS; (3) many wastes did not meet the pretreatment standards and exhibited high Microtox toxicity; (4) some wastes exhibited high Microtox toxicity, although they met the pretreatment standards; (5) the mixture of the individual wastes exhibited an antagonistic effect; (6) the activated sludge process removed 60-75% of influent toxicity; and (7) the final effluent sometimes showed an increase in Microtox toxicity.


2018 ◽  
Vol 2018 (4) ◽  
pp. 103-117
Author(s):  
Bipin Pathak ◽  
Ahmed Al-Omari ◽  
Scott Smith ◽  
Nicholas Passarelli ◽  
Ryu Suzuki ◽  
...  

2019 ◽  
Vol 290 ◽  
pp. 02007
Author(s):  
Radu Dan Paltan ◽  
Cristina Biriş ◽  
Loredana Anne-Marie Rădulescu

Of many techniques that are used to optimize production and costs, the studies conducted within a profile company lead to our choice for testing the 6Sigma method (the most used method in the automotive industry) in view of the economic efficiency applied in the wood Industry company. This method measures how many flaws exist in a process and determines in a systematic way how to improve it by technical overhauling and eliminating or minimizing the process for efficiency. This research article aims to study the state of research on the optimization of the production process through technical overhauling for panels reconstituted from solid wood and ways to make production more efficient by cutting costs through technical overhauling. From preliminary research, we estimate that all the items founded and others that will result from further research will result in a significant decrease in production costs that are reflected in the cost of the finished product and consequently in increasing the yield of the company by maximizing its profit. At the same time it may be the basis of future research studies in the field. The easier it is to maximize profits, the lower the operating costs are and the higher recovery rate of investments are, that will result a change in the operating mode: “working smarter not harder”.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Leilah Krounbi ◽  
Akio Enders ◽  
John Gaunt ◽  
Margaret Ball ◽  
Johannes Lehmann

AbstractThe conversion of dairy waste with high moisture contents to dry fertilizers may reduce environmental degradation while lowering crop production costs. We converted the solid portion of screw-pressed dairy manure into a sorbent for volatile ammonia (NH3) in the liquid fraction using pyrolysis and pre-treatment with carbon dioxide (CO2). The extractable N in manure biochar exposed to NH3 following CO2 pre-treatment reached 3.36 g N kg−1, 1260-fold greater extractable N than in untreated manure biochar. Ammonia exposure was 142-times more effective in increasing extractable N than immersing manure biochar in the liquid fraction containing dissolved ammonium. Radish and tomato grown in horticultural media with manure biochar treated with CO2 + NH3 promoted up to 35% greater plant growth (dry weight) and 36–83% greater N uptake compared to manure biochar alone. Uptake of N was similar between plants grown with wood biochar exposed to CO2 + NH3, compared to N-equivalent treatments. The available N in dairy waste in New York (NY) state, if pyrolyzed and treated with NH3 + CO2, is equivalent to 11,732–42,232 Mg N year−1, valued at 6–21.5 million USD year−1. Separated dairy manure treated with CO2 + NH3 can offset 23–82% of N fertilizer needs of NY State, while stabilizing both the solid and liquid fraction of manure for reduced environmental pollution.


1999 ◽  
Vol 89 (3) ◽  
pp. 585-604 ◽  
Author(s):  
Stephen W Salant ◽  
Greg Shaffer

Oligopoly models where prior actions by firms affect subsequent marginal costs have been useful in illuminating policy debates in areas such as antitrust regulation, environmental protection, and international competition. We discuss properties of such models when a Cournot equilibrium occurs at the second stage. Aggregate production costs strictly decline with no change in gross revenue or gross consumer surplus if the prior actions strictly increase the variance of marginal costs without changing the marginal-cost sum. Therefore, unless the cost of inducing second-stage asymmetry more than offsets this reduction in production costs, the private and social optima are asymmetric. (JEL D43, L13, L40)


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