scholarly journals A Review of Energy Consumption in the Acquisition of Bio-Feedstock for Microalgae Biofuel Production

2021 ◽  
Vol 13 (16) ◽  
pp. 8873
Author(s):  
Minghao Chen ◽  
Yixuan Chen ◽  
Qingtao Zhang

Microalgae biofuel is expected to be an ideal alternative to fossil fuels to mitigate the effects of climate change and the energy crisis. However, the production process of microalgae biofuel is sometimes considered to be energy intensive and uneconomical, which limits its large-scale production. Several cultivation systems are used to acquire feedstock for microalgal biofuels production. The energy consumption of different cultivation systems is different, and the concentration of culture medium (microalgae cells contained in the unit volume of medium) and other properties of microalgae vary with the culture methods, which affects the energy consumption of subsequent processes. This review compared the energy consumption of different cultivation systems, including the open pond system, four types of closed photobioreactor (PBR) systems, and the hybrid cultivation system, and the energy consumption of the subsequent harvesting process. The biomass concentration and areal biomass production of every cultivation system were also analyzed. The results show that the flat-panel PBRs and the column PBRs are both preferred for large-scale biofuel production for high biomass productivity.

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Hossein Alishah Aratboni ◽  
Nahid Rafiei ◽  
Raul Garcia-Granados ◽  
Abbas Alemzadeh ◽  
José Rubén Morones-Ramírez

Abstract The use of fossil fuels has been strongly related to critical problems currently affecting society, such as: global warming, global greenhouse effects and pollution. These problems have affected the homeostasis of living organisms worldwide at an alarming rate. Due to this, it is imperative to look for alternatives to the use of fossil fuels and one of the relevant substitutes are biofuels. There are different types of biofuels (categories and generations) that have been previously explored, but recently, the use of microalgae has been strongly considered for the production of biofuels since they present a series of advantages over other biofuel production sources: (a) they don’t need arable land to grow and therefore do not compete with food crops (like biofuels produced from corn, sugar cane and other plants) and; (b) they exhibit rapid biomass production containing high oil contents, at least 15 to 20 times higher than land based oleaginous crops. Hence, these unicellular photosynthetic microorganisms have received great attention from researches to use them in the large-scale production of biofuels. However, one disadvantage of using microalgae is the high economic cost due to the low-yields of lipid content in the microalgae biomass. Thus, development of different methods to enhance microalgae biomass, as well as lipid content in the microalgae cells, would lead to the development of a sustainable low-cost process to produce biofuels. Within the last 10 years, many studies have reported different methods and strategies to induce lipid production to obtain higher lipid accumulation in the biomass of microalgae cells; however, there is not a comprehensive review in the literature that highlights, compares and discusses these strategies. Here, we review these strategies which include modulating light intensity in cultures, controlling and varying CO2 levels and temperature, inducing nutrient starvation in the culture, the implementation of stress by incorporating heavy metal or inducing a high salinity condition, and the use of metabolic and genetic engineering techniques coupled with nanotechnology.


Author(s):  
Yuting Luo ◽  
Zhiyuan Zhang ◽  
Fengning Yang ◽  
Jiong Li ◽  
Zhibo Liu ◽  
...  

Large-scale production of green hydrogen by electrochemical water splitting is considered as a promising technology to address critical energy challenges caused by the extensive use of fossil fuels. Although nonprecious...


Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 463 ◽  
Author(s):  
Ali Nawaz Kumbhar ◽  
Meilin He ◽  
Abdul Razzaque Rajper ◽  
Khalil Ahmed Memon ◽  
Muhammad Rizwan ◽  
...  

The decline in fossil fuel reserves has forced researchers to seek out alternatives to fossil fuels. Microalgae are considered to be a promising feedstock for sustainable biofuel production. Previous studies have shown that urea is an important nitrogen source for cell growth and the lipid production of microalgae. The present study investigated the effect of different concentrations of urea combined with kelp waste extract on the biomass and lipid content of Chlorella sorokiniana. The results revealed that the highest cell density, 20.36 × 107 cells−1, and maximal dry biomass, 1.70 g/L, were achieved in the presence of 0.5 g/L of urea combined with 8% kelp waste extract. Similarly, the maximum chlorophyll a, b and beta carotenoid were 10.36 mg/L, 7.05, and 3.01 mg/L, respectively. The highest quantity of carbohydrate content, 290.51 µg/mL, was achieved in the presence of 0.2 g/L of urea and 8% kelp waste extract. The highest fluorescence intensity, 40.05 × 107 cells−1, and maximum total lipid content (30%) were achieved in the presence of 0.1 g/L of urea and 8% kelp waste extract. The current study suggests that the combination of urea and kelp waste extract is the best strategy to enhance the biomass and lipid content in Chlorella sorokiniana.


2014 ◽  
Vol 1008-1009 ◽  
pp. 1470-1476
Author(s):  
Chang An Ye ◽  
Xiao Fen Zhang

Polycrystalline silicon-photovoltaic industry belongs to high-and-new technology industry, but it produces massive by-products (silicon tetrachloride and so on), even partial chloro-silicane and hydrogen chloride exude into the exhaust in its production process. As a consequence, it not only increases the exhaust processing cost in the polycrystalline silicon-photovoltaic industry, but also increases pollutant discharge of the enterprise. At present, Chinese polycrystalline silicon-photovoltaic enterprises cannot solve technical difficult problems in large-scale production due to lack of coordination of chemical industry. Moreover, polycrystalline silicon has high request of purity that needs quite advanced technology to achieve. This article introduces influences upon production cost and energy consumption with the use of improved Siemens method, and proposes that polytrophic-photovoltaic industry needs to be systematized, normalized and standardized for its healthy development.


Author(s):  
Thomas Jenkins ◽  
Aurélie Bovi ◽  
Robert Edwards

Depletion of oil reserves and the associated effects on climate change have prompted a re-examination of the use of plant biomass as a sustainable source of organic carbon for the large-scale production of chemicals and materials. While initial emphasis has been placed on biofuel production from edible plant sugars, the drive to reduce the competition between crop usage for food and non-food applications has prompted massive research efforts to access the less digestible saccharides in cell walls (lignocellulosics). This in turn has prompted an examination of the use of other plant-derived metabolites for the production of chemicals spanning the high-value speciality sectors through to platform intermediates required for bulk production. The associated science of biorefining, whereby all plant biomass can be used efficiently to derive such chemicals, is now rapidly developing around the world. However, it is clear that the heterogeneity and distribution of organic carbon between valuable products and waste streams are suboptimal. As an alternative, we now propose the use of synthetic biology approaches to ‘re-construct’ plant feedstocks for optimal processing of biomass for non-food applications. Promising themes identified include re-engineering polysaccharides, deriving artificial organelles, and the reprogramming of plant signalling and secondary metabolism.


2021 ◽  
Vol 257 ◽  
pp. 03008
Author(s):  
Muxin Hu ◽  
Dichen Zhao ◽  
Qiuchi Jin ◽  
Hanrui Li ◽  
Wenmin Wang

In recognition of the increasing demand of energy and the worsening environmental problems linked with fossil fuels usage, algal biofuel has been proposed as one of the alternative energy sources. It has become one of the hottest topics in renewable energy field in the new century, especially over the past decade. In this review, we summarized the characteristics of different types of algae biofuels. Besides, an in-depth evaluation of the systematic cultivation and practical application of algae have been conducted. Although algal biofuel has a great potential, its unacceptably high cost limits the large-scale industrialization. In order to resolve such restrictions, feasible methods of improving the large scale production and practical application of algal biofuels are proposed. Future efforts should be focused not only on the cost reduction and innovation techniques, but also towards high value by-products to maximize economic benefits. Our results are dedicated to provide valuable references for subsequent research and guidelines on algae biofuels field.


Author(s):  
BB Marvey

Large fluctuations in crude oil prices and the diminishing oil supply have left economies vulnerable to energy shortages thus placing an enormous pressure on nations around the world to seriously consider alternative renewable resources as feedstock in biofuel applications. Apart from energy security reasons, biofuels offer other advantages over their petroleum counterparts in that they contribute to the reduction in green- house gas emissions and to sustainable development. Just a few decades after discontinuing its large scale production of bioethanol for use as en- gine fuel, South Africa (SA) is again on its way to resuscitating its biofuel industry. Herein an overview is presented on South Africa’s oilseed and biofuel production, biofuels industrial strategy, industry readiness, chal- lenges in switching to biofuels and the strategies to overcome potential obstacles.


2012 ◽  
Vol 5 (1) ◽  
pp. 103-116 ◽  
Author(s):  
Silvia-Juliana Jerez-Mogollón ◽  
Laura-Viviana Rueda-Quiñonez ◽  
Laura-Yulexi Alfonso-Velazco ◽  
Andrés-Fernando Barajas-Solano ◽  
Crisóstomo Barajas-Ferreira ◽  
...  

This work studied the improvement of biomass and carbohydrate (glucose and xylose) lab–scale productivity in Chlorella vulgaris UTEX 1803 through the use of the carbon/nitrogen ratio. In order to do so, mixotrophic cultures were made by the modification of initial concentration of CH3COONa (5, 10 and 20 mM) and NaNO3 (0.97, 1.94 and 2.94 mM). All treatments were maintained at 23 ± 1ºC, with light/dark cycles of 12h : 12h for 5 days.It was found that in addition to the carbon/nitrogen ratio, time also influences the concentration of biomass and carbohydrates. The treatment containing 10 mM acetate: 1.94 mM nitrate, reached a concentration of 0.79 g/L of biomass, 76.9 μg/mL of xylose and 73.7 μg/mL of glucose in the fifth day. However, the treatmentcontaining 20 mM acetate: 0.97 mM nitrate produced 1.04 g/L of biomass, 78.9 μg/mL of xylose and 77.2 μg/mL of glucose in the third day, while in the same day the treatment containing 0 mM acetate: 2.94 mM nitrate, produced 0.55 g/L of biomass, 40.2 μg/mL of xylose and 31.3 μg/mL of glucose.The use of carbon/nitrogen ratios improved biomass productivity (from 0.55 to 1.04 g/L) as well as xylose (from 40.2 to 78.9 μg/mL) and glucose (from 31.3 to 77.2 μg/mL) concentration, representing an improvement of up to two times the production of both biomass and carbohydrates in only 3 days of culture.


2012 ◽  
Vol 260-261 ◽  
pp. 28-33
Author(s):  
Jun Zhang ◽  
Lu Cheng Ji ◽  
Bo Jin

Hydrogen energy has been considered as a clean alternative energy source substituting fossil fuels. Many countries consider it as the ultimate solution to the energy and environmental problems, even draw up the blueprint of “hydrogen economy” and heavily invest for research and development. However, after decades of research, the hydrogen energy technologies are still being prospective and explored, and haven’t been put into large scale production by now. This article begins with expatiation on the essence of hydrogen energy, makes analysis of various big challenges for hydrogen energy technologies, and reaches the conclusion that we should hold the rational and cautious attitude towards hydrogen energy source because the transition to hydrogen economy of unclear prospect must pay a very high cost, which is unbearable for the social and economic development status of developing countries.


2020 ◽  
Vol 63 (4) ◽  
pp. 355-370 ◽  
Author(s):  
Guang Gao ◽  
James Grant Burgess ◽  
Min Wu ◽  
Shujun Wang ◽  
Kunshan Gao

AbstractThe rising global demand for energy and the decreasing stocks of fossil fuels, combined with environmental problems associated with greenhouse gas emissions, are driving research and development for alternative and renewable sources of energy. Algae have been gaining increasing attention as a potential source of bio-renewable energy because they grow rapidly, and farming them does not, generally, compete for agricultural land use. Previous studies of algal biofuels have focused on microalgae because of their fast growth rate and high lipid content. Here we analyze the multiple merits of biofuel production using macroalgae, with particular reference to their chemical composition, biomass and biofuel productivity, and cost-effectiveness. Compared to microalgae, macroalgae have lower growth rates and energy productivity but higher cost-effectiveness. A biomass productivity of over 73.5 t dry mass ha−1 year−1 with a methane yield of 285 m3 t−1 dry mass would make electricity production from macroalgae profitable, and this might be achieved using fast-growing macroalgae, such as Ulva. Taking into account the remediation of eutrophication and CO2, exploring macroalgae for a renewable bioenergy is of importance and feasible.


Sign in / Sign up

Export Citation Format

Share Document