scholarly journals A Comparative Study of Bioprocess Performance for Improvement of Bioethanol Production from Macroalgae

2019 ◽  
Vol 33 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Benan İnan ◽  
Didem Özçimen

In the last decade, studies that have focused on biodiesel production from algal biomass have been replaced with bioethanol production from algae, because bioethanol production from algae seems more promising when assessed on economic terms. Most coastal areas are covered with macroalgae, which are considered as a waste, and thus become a great problem for the municipality. Instead of their disposal, they can be alternatively utilized for bioethanol production. In this study, macroalgae located in the coastal regions of the Marmara Sea were collected and utilized for bioethanol production, and effects of the concentration of pre-treatment chemicals, pre-treatment temperature, and pre-treatment time on bioethanol yield were investigated. The highest bioethanol yields for dilute acid and alkaline pre-treatments were obtained under the conditions of 2 N sulfuric acid and 0.15 N potassium hydroxide solutions at the pre-treatment temperature of 100 °C and pre-treatment time of 60 minutes.

Author(s):  
. Shivangi ◽  
Rohit Raina ◽  
Manish Mishra ◽  
Shelly Sehgal

Background: Energy production and consumption ratio form the hallmark of the economic prosperity of a country. To keep up with the demand and supply of energy a major switch to biofuels is reasoned but the cost associated with production and the choice of raw material forms two major economical and ethical concerns, especially in the under-developed and developing countries where the food is not sufficiently available to everyone. In this scenario, the use of food sources as raw material becomes unjustified. Purpose: To address these issues, here we made an effort to obtain bioethanol from a non-edible and easily available resource that requires a modest cost of production i.e., a locally available algal bloom. Also, different methods of pre-treatment were employed and scrutinized for their efficacy. These methods of pre-treatment are very cost-effective and easy to administer. Materials and Methods: The algal biomass was pre-treated separately in three ways viz., freeze-thawing, mechanical disruption and rotten wood treatment. The algal cake left out after extraction of lipid content for biodiesel production was also used as a fourth sample. After pre-treatment, the supernatant was collected and estimated for reducing sugar content and allowed to ferment using Saccharomyces cerevisiae. A distillate was obtained and checked for ethanol percentage through gas chromatography. Results: The mechanically disrupted sample yielded the highest percentage of ethanol followed by algal cake, freeze-thawing and rotten wood treatment. Conclusion: Given present food scarcity, the non-edible algae could be a better alternative for bioethanol production as compared to the use of conventional food crops. Through this study, we have found that a better yield can be achieved if the algal biomass is pre-treated via mechanical disruption.


Author(s):  
Samar A. El-Mekkawi ◽  
Sayeda M. Abdo ◽  
Farag A. Samhan ◽  
Gamila H. Ali

Abstract Background Algal biomass fermentation is one of the promising alternatives for bioethanol production. The bioethanol yield relies on fermentation conditions as the algal biomass amount, the yeast volume (% v/v), and the fermentation time. In this work, algal biomass harvested from a pilot-scale high rate algal pond (HRAP) was fermented anaerobically using immobilized Saccharomyces cerevisiae (ATCC 4126). The HRAP was constructed at the Zenin wastewater treatment plant (WTP), Giza, Egypt. A separate hydrolysis fermentation process (SHF) was applied for algal biomass. The effect of the algal biomass amount, the yeast volume (% v/v), and the time of fermentation as three independent variables were studied simultaneously and analyzed statistically using Design-Expert software V6.0.8. Results The harvested algal biomass from HRAP contains 45% carbohydrates and was dominated by Microcystis sp. The results revealed that optimum bioethanol yield 18.57 g/L is achieved by fermenting 98.7 g/L algae using 15.09% of the volume immobilized yeast for 43.6 h with a 95% confidence interval. Conclusion Microalgae grown on wastewater are a promising source of bioethanol production. Maximizing the ethanol production is achieved by optimizing the fermentation parameters as algal biomass, fermentation time, and yeast volume percent. The simultaneous optimization of the parameters using a statistical program is an effective way to maximize the production and predict a model that describes the relationship between these parameters and their response. The prospective research is going to study the effect of these predicted parameters on continuous fermentation on the semi-pilot scale.


2017 ◽  
Vol 28 (3) ◽  
pp. 1 ◽  
Author(s):  
Charlie Marembu Dodo ◽  
Samphson Mamphweli ◽  
Omobola Okoh

Bioethanol production is one of the most promising possible substitutes for fossil-based fuels, but there is a need to make available cost-effective methods of production if it is to be successful. Various methods for the production of bioethanol using different feedstocks have been explored. Bioethanol synthesis from sugarcane, their tops and leaves have generally been regarded as waste and discarded. This investigation examined the use of lignocellulosic sugarcane leaves and tops as biomass and evaluated their hydrolysate content. The leaves and tops were hydrolysed using concentrated and dilute sulphuric acid and compared with a combination of oxidative alkali-peroxide pre-treatment with enzyme hydrolysis using the enzyme cellulysin® cellulase. Subsequent fermentation of the hydrolysates into bioethanol was done using the yeast saccharomyces cerevisae. The problem of acid hydrolysis to produce inhibitors was eliminated by overliming using calcium hydroxide and this treatment was subsequently compared with sodium hydroxide neutralisation. It was found that oxidative alkali pre-treatment with enzyme hydrolysis gave the highest yield of fermentable sugars of 38% (g/g) for 7% (v/v) peroxide pretreated biomass than 36% (g/g) for 5% (v/v) with the least inhibitors. Concentrated and dilute acid hydrolysis each gave yields of 25% (g/g) and 22% (g/g) respectively, although the acid required a neutralisation step, resulting in dilution. Alkaline neutralisation of acid hydrolysates using sodium hydroxide resulted in less dilution and loss of fermentable sugars, compared with overliming. Higher yields of bioethanol of 13.7 g/l were obtained from enzyme hydrolysates than the 6.9 g/l ethanol from dilute acid hydrolysates. There was more bioethanol yield of 13.7 g/l after 72 hours of fermentation with the yeast than the 7.0 g/l bioethanol after 24 hours.This research showed that it is possible to use sugarcane waste material to supplement biofuel requirements and that combining the chemical and biological methods of pretreatments can give higher yields at a faster rate.


2011 ◽  
Vol 36 (9) ◽  
pp. 2424-2432 ◽  
Author(s):  
Anil Kuruvilla Mathew ◽  
Keith Chaney ◽  
Mitch Crook ◽  
Andrea Claire Humphries

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 128-129
Author(s):  
Kevin S Jerez Bogota ◽  
Tofuko A Woyengo ◽  
William Gibbons

Abstract Pre-treatment of whole stillage (WS; slurry material that is dried into DDGS) with heat can improve digestibility of the resulting DDGS by pigs. A study was conducted to identify optimal conditions (time and temperature) for heat pre-treatment of corn WS. Six samples of WS from different sources were divided into 13 sub-samples to give a total of 78 sub-samples. Thirteen treatments were applied to 13 sub-samples from each source (1 sub-sample/treatment). The treatments were untreated WS, and WS that was pre-treated (70 psi) for 10, 20, or 30 minutes and at 100, 120, 140, or 160 °C in a 3 × 4 factorial arrangement. Sub-samples were subjected to in vitro digestion with porcine pepsin and pancreatin, followed by in vitro fermentation for 72 h. Accumulated gas production was recorded and modeled to estimate kinetics of gas production. Volatile fatty acids (VFA) concentration in fermented solutions was also measured. Pre-treatment time and temperature did not interact on in vitro digestibility of DM (IVDDM), and total gas and VFA production. Pre-treatment time did not affect total gas and VFA production. The IVDDM for untreated WS was 73.4%. An increase in pre-treatment temperature from 100 to 160 °C resulted in linear and quadratic increase in IVDDM by 11%. Response surface analysis indicated that maximum IVDDM resulted from relatively long pre-treatment times (20–30 mins) and highest pre-treatment temperature. An increase in pre-treatment temperature from 100 to 160 °C resulted in linear increase in total gas production by 13%; maximum total gas production resulted from relatively short pre-treatment times (10–20 mins) and highest pre-treatment temperature. Total VFA production was unaffected by pre-treatment time. In conclusion, in vitro digestibility and fermentability of WS was improved by heat pre-treatment. Optimal conditions for pre-treatment of WS for combined improved digestibility and fermentability were 160 °C and 20 mins.


Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1324 ◽  
Author(s):  
Sanjeet Mehariya ◽  
Angela Iovine ◽  
Giuseppe Di Sanzo ◽  
Vincenzo Larocca ◽  
Maria Martino ◽  
...  

Lutein has several benefits for human health, playing an important role in the prevention of age-related macular degeneration (AMD), cataracts, amelioration of the first stages of atherosclerosis, and some types of cancer. In this work, the Scenedesmus almeriensis microalga was used as a natural source for the supercritical fluid (SF) extraction of lutein. For this purpose, the optimization of the main parameters affecting the extraction, such as biomass pre-treatment, temperature, pressure, and carbon dioxide (CO2) flow rate, was performed. In the first stage, the effect of mechanical pre-treatment (diatomaceous earth (DE) and biomass mixing in the range 0.25–1 DE/biomass; grinding speed varying between 0 and 600 rpm, and pre-treatment time changing from 2.5 to 10 min), was evaluated on lutein extraction efficiency. In the second stage, the influence of SF-CO2 extraction parameters such as pressure (25–55 MPa), temperature (50 and 65 °C), and CO2 flow rate (7.24 and 14.48 g/min) on lutein recovery and purity was investigated. The results demonstrated that by increasing temperature, pressure, and CO2 flow rate lutein recovery and purity were improved. The maximum lutein recovery (~98%) with purity of ~34% was achieved operating at 65 °C and 55 MPa with a CO2 flow rate of 14.48 g/min. Therefore, optimum conditions could be useful in food industries for lutein supplementation in food products.


2021 ◽  
Vol 13 (4) ◽  
pp. 1970
Author(s):  
Sara Yasipourtehrani ◽  
Vladimir Strezov ◽  
Tao Kan ◽  
Tim Evans

Blast Furnace Slag (BFS) is a by-product of the iron ore processing industry with potential to be used in different industrial applications. In this research, BFS was used to examine its ability for dye removal from wastewater. The efficiency of two types of BFS samples for removal of cationic methylene blue (MB) and acidic methyl orange (MO) dyes was investigated and results found that the optimal conditions for treatment of wastewater were 80 g/L of adsorbent dose and 1 h of treatment time for both dyes. BFS was found to be more effective for removal of the acidic MO dye than the cationic MB dye. Under shorter residence times, the results showed reverse trends with BFS samples removing higher concentrations of MB than MO. The BFS chemistry had additional impacts on the efficiency of dye removal. Higher basicity of BFS had lower dye removal ability for adsorption of acidic dye when applied at smaller concentrations, while for cationic dye when applied at higher concentrations. The results showed that BFS has potential role for pre-treatment of industrial wastewater contaminated with dyes and may contribute to reduced use of more expensive adsorbents, such as activated carbons.


1984 ◽  
Vol 35 (2) ◽  
pp. 115 ◽  
Author(s):  
DJ Mares

Germinability in harvest-mature wheat grain showed a marked dependence on temperature. The optimum temperature for the complete germination of all grains ranged from 20�C for the non-dormant variety, Timgalen, to 10�C for the strongly dormant red wheat RL 4137, whereas the optimum in terms of the shortest lag period ranged from 25� to 15�C for the same varieties. Germinability gradually increased during post-harvest storage and, for after-ripened grain, the optimum temperature for both complete germination and shortest lag period were greater than 30�C. Germinability could also be increased by pre-treating imbibing grains at temperatures of 5�, 10� or in some cases 15�C. This treatment was only effective for grain at moisture contents >25% (dry weight) and the effect was not reversed by redesiccation. The pre-treatment temperature required for maximum germinability decreased with increasing levels of grain dormancy. Complete removal of dormancy required a pre-treatment period of c. 48 h; however, lesser periods gave the shortest lag period in the case of the dormant varieties. The implications of these results for the utilization of dormancy in the development of preharvest sprouting damage tolerant varieties and their subsequent use in practice are discussed.


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