scholarly journals High Gravity Fermentation of Sugarcane Bagasse Hydrolysate by Saccharomyces pastorianus to Produce Economically Distillable Ethanol Concentrations: Necessity of Medium Components Examined

Fermentation ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 8 ◽  
Author(s):  
Sarah W. Harcum ◽  
Thomas P. Caldwell

A major economic obstacle in lignocellulosic ethanol production is the low sugar concentrations in the hydrolysate and subsequent fermentation to economically distillable ethanol concentrations. We have previously demonstrated a two-stage fermentation process that recycles xylose with xylose isomerase to increase ethanol productivity, where the low sugar concentrations in the hydrolysate limit the final ethanol concentrations. In this study, three approaches are combined to increase ethanol concentrations. First, the medium-additive requirements were investigated to reduce ethanol dilution. Second, methods to increase the sugar concentrations in the sugarcane bagasse hydrolysate were undertaken. Third, the two-stage fermentation process was recharacterized with high gravity hydrolysate. It was determined that phosphate and magnesium sulfate are essential to the ethanol fermentation. Additionally, the Escherichia coli extract and xylose isomerase additions were shown to significantly increase ethanol productivity. Finally, the fermentation on hydrolysate had only slightly lower productivity than the reagent-grade sugar fermentation; however, both fermentations had similar final ethanol concentrations. The present work demonstrates the capability to produce ethanol from high gravity sugarcane bagasse hydrolysate using Saccharomyces pastorianus with low yeast inoculum in minimal medium. Moreover, ethanol productivities were on par with pilot-scale commercial starch-based facilities, even when the yeast biomass production stage was included.

2006 ◽  
Vol 73 (3) ◽  
pp. 815-824 ◽  
Author(s):  
Lies Blieck ◽  
Geert Toye ◽  
Fran�oise Dumortier ◽  
Kevin J. Verstrepen ◽  
Freddy R. Delvaux ◽  
...  

ABSTRACT To save energy, space, and time, today's breweries make use of high-gravity brewing in which concentrated medium (wort) is fermented, resulting in a product with higher ethanol content. After fermentation, the product is diluted to obtain beer with the desired alcohol content. While economically desirable, the use of wort with an even higher sugar concentration is limited by the inability of brewer's yeast (Saccharomyces pastorianus) to efficiently ferment such concentrated medium. Here, we describe a successful strategy to obtain yeast variants with significantly improved fermentation capacity under high-gravity conditions. We isolated better-performing variants of the industrial lager strain CMBS33 by subjecting a pool of UV-induced variants to consecutive rounds of fermentation in very-high-gravity wort (>22� Plato). Two variants (GT336 and GT344) showing faster fermentation rates and/or more-complete attenuation as well as improved viability under high ethanol conditions were identified. The variants displayed the same advantages in a pilot-scale stirred fermenter under high-gravity conditions at 11�C. Microarray analysis identified several genes whose altered expression may be responsible for the superior performance of the variants. The role of some of these candidate genes was confirmed by genetic transformation. Our study shows that proper selection conditions allow the isolation of variants of commercial brewer's yeast with superior fermentation characteristics. Moreover, it is the first study to identify genes that affect fermentation performance under high-gravity conditions. The results are of interest to the beer and bioethanol industries, where the use of more-concentrated medium is economically advantageous.


2017 ◽  
pp. 534-537
Author(s):  
Nico Antens ◽  
Jan L.M. Struijs

At beet sugar production, vapors from first and second carbonatation contain a significant amount of odor components, NH3 and waste heat, which are normally directly released into the environment. Due to sustainability motivations, obligations regarding odor nuisance and expected stricter regulations regarding NH3 emission limits, Suiker Unie decided to take measures to reduce emission via the carbonatation vapors. During the 2015 beet campaign, pilot scale plant trials have been performed to investigate the effectiveness of indirect contact and direct contact condensation of these vapors. Based on this experimental work a two-stage gas scrubbing concept was designed: in the first stage main goal is condensing the vapors and reuse the heat of condensation to heat up limed juice, while the actual scrubbing takes place in the second scrubber. This two-stage gas scrubbing installation has been built at the Vierverlaten factory and was started up in the 2016 beet campaign. The background, pilot scale trials, concept of design and achieved reductions in odor and NH3 emission at industrial scale are discussed.


1998 ◽  
Vol 38 (1) ◽  
pp. 327-334 ◽  
Author(s):  
P. Pavan ◽  
P. Battistoni ◽  
P. Traverso ◽  
A. Musacco ◽  
F. Cecchi

The paper presents results coming from experiments on pilot scale plants about the possibility to integrate the organic waste and wastewater treatment cycles, using the light organic fraction produced via anaerobic fermentation of OFMSW as RBCOD source for BNR processes. The effluent from the anaerobic fermentation process, with an average content of 20 g/l of VFA+ lactic acid was added to wastewater to be treated in order to increase RBCOD content of about 60-70 mg/l. The results obtained in the BNR process through the addition of the effluent from the fermentation unit are presented. Significant increase of denitrification rate was obtained: 0.06 KgN-NO3/KgVSS d were denitrified in the best operative conditions studied. -Vmax shows values close to those typical of the pure methanol addition (about 0.3 KgN-NO3/KgVSS d). A considerable P release (35%) was observed in the anaerobic step of the BNR process, even if not yet a completely developed P removal process.


2021 ◽  
Vol 13 (3) ◽  
pp. 1109
Author(s):  
Edgar Ricardo Oviedo-Ocaña ◽  
Angélica María Hernández-Gómez ◽  
Marcos Ríos ◽  
Anauribeth Portela ◽  
Viviana Sánchez-Torres ◽  
...  

The composting of green waste (GW) proceeds slowly due to the presence of slowly degradable compounds in that substrate. The introduction of amendments and bulking materials can improve organic matter degradation and end-product quality. However, additional strategies such as two-stage composting, can deal with the slow degradation of green waste. This paper evaluates the effect of two-stage composting on the process and end-product quality of the co-composting of green waste and food waste amended with sawdust and phosphate rock. A pilot-scale study was developed using two treatments (in triplicate each), one being a two-stage composting and the other being a traditional composting. The two treatments used the same mixture (wet weight): 46% green waste, 19% unprocessed food waste, 18% processed food waste, 13% sawdust, and 4% phosphate rock. The traditional composting observed a higher degradation rate of organic matter during the mesophilic and thermophilic phases and observed thermophilic temperatures were maintained for longer periods during these two phases compared to two-stage composting (i.e., six days). Nonetheless, during the cooling and maturation phases, the two treatments had similar behaviors with regard to temperature, pH, and electrical conductivity, and the end-products resulting from both treatments did not statistically differ. Therefore, from this study, it is concluded that other additional complementary strategies must be evaluated to further improve GW composting.


Fuel ◽  
2019 ◽  
Vol 254 ◽  
pp. 115653 ◽  
Author(s):  
Sheetal Bandhu ◽  
Neha Bansal ◽  
Diptarka Dasgupta ◽  
Vivek Junghare ◽  
Arushdeep Sidana ◽  
...  

2021 ◽  
Vol 39 ◽  
pp. 101873
Author(s):  
Qiming Guo ◽  
Zhihong Yang ◽  
Qun Zhao ◽  
Jing Chen ◽  
Jie Li ◽  
...  
Keyword(s):  

2010 ◽  
Vol 18 ◽  
pp. S72-S80 ◽  
Author(s):  
Domenico Foglia ◽  
Mattias Ljunggren ◽  
Walter Wukovits ◽  
Anton Friedl ◽  
Guido Zacchi ◽  
...  

2020 ◽  
pp. 249-308
Author(s):  
Sompong O-Thong ◽  
Chonticha Mamimin ◽  
Prawit Kongjan ◽  
Alissara Reungsang

1994 ◽  
Vol 30 (3) ◽  
pp. 173-181 ◽  
Author(s):  
L. Knudsen ◽  
J. A. Pedersen ◽  
J. Munck

The work presented in this paper concerns the application of a two-stage aerobic activated sludge process for treatment of effluents from paper mills in Denmark. The paper describes both pilot-scale test results and fullscale experience with the process. The treatment process is characterised by a bigh-load first stage (2-4 kg COD/kg MLSSxd) followed by a low-load second stage to secure full nitrification and denitrification of remaining nitrogen compounds. The results of continuous pilot-scale tests show that it is possible to obtain a reduction of more than 85% of the incoming COD,01 and a 99% reduction of the incoming BOD5, resulting in an effluent quality of 230 mg CODsol/l and less than 10 mg BOD5/l. As indicated, practically all the biodegradable organic substances are removed by the process. The remaining fraction of soluble organics measured as COD is considered to be non-biodegradable by conventional biological treatment systems. The results produced in the pilot-scale tests are confirmed by the effluent qualities obtained in a full-scale treatment plant at another paper mill, involving an identical process concept. During the pilot-scale tests, special attention bas been paid to the removal of organic compounds, organic nitrogen as well as nutrients and nitrification. In addition, the sludge characteristics and the oxygen requirements have been considered.


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