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

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

Effect of Process Parameters on Chitosan-mediated Microalgae Flocculation

Today, microalgae have received considerable interest as an alternative feedstock for biofuel, animal feed, human food, and pharmaceuticals because they possess valuable oils and biomolecules. The main problem of the cost of microalgae production is generally associated with the harvesting process. Flocculation is an effective method to harvest microalgal biomass and minimize the operating cost. In this study, the effect of the chitosan solution, different pH conditions, and flocculation time on flocculation process of Chlorella minutissima and Nannochloropsis oculata were investigated, and the obtained data were evaluated statistically. Flocculation efficiency of C. minutissima and N. oculata were the highest under the conditions of 10 pH, 100 mg L–1 chitosan concentration, and flocculation time of 60 min, and found as 97 % and 85 %. It was also found that chitosan flocculation could be improved with pH increase. This study showed that chitosan is a favorable flocculant because of its high efficiency, being non-toxic, and enabling the reusability of the growth medium after flocculation

Adsorption of lead and copper on bentonite and grapeseed activated carbon in single- and binary-ion systems

In this study, bentonite originating from Turkey (Eskiehir province) and activated carbon obtained from grapeseed were used as adsorbents for the removal of lead (Pb2+) and copper (Cu2+) ions from aqueous solutions. Experiments were performed in single- and binary-ion systems at constant temperature of 298 K and pH value of 5. In order to describe the adsorption mechanism Langmuir, Freundlich and Temkin isotherms were used. The total adsorption capacity values of adsorbents were compared. It was observed that the total adsorption capacity values were changed depending on the type of adsorbent used, type of metal ion and interaction between metal ions

Techno-economics and Sensitivity Analysis of Microalgae as Commercial Feedstock for Bioethanol Production

© 2019 American Institute of Chemical Engineers The foremost purpose of this techno-economic analysis (TEA) modeling was to predict a harmonized figure of comprehensive cost analysis for commercial bioethanol generation from microalgae species in Brunei Darussalam based on the conventional market scenario. This model was simulated to set out economic feasibility and probabilistic assumption for large-scale implementations of a tropical microalgae species, Chlorella vulgaris, for a bioethanol plant located in the coastal area of Brunei Darussalam. Two types of cultivation systems such as closed system (photobioreactor—PBR) and open pond approaches were anticipated for a total approximate biomass of 220 t year−1 on 6 ha coastal areas. The biomass productivity was 56 t ha−1 for PBR and 28 t ha−1 for pond annually. The plant output was 58.90 m3 ha−1 for PBR and 24.9 m3 ha−1 for pond annually. The total bioethanol output of the plant was 57,087.58 gal year−1 along with the value added by-products (crude bio-liquid and slurry cake). The total production cost of this project was US$2.22 million for bioethanol from microalgae and total bioethanol selling price was US$2.87 million along with the by-product sale price of US$1.6 million. A sensitivity analysis was conducted to forecast the uncertainty of this conclusive modeling. Different data sets through sensitivity analysis also presented positive impacts of economical and environmental views. This TEA model is expected to be initialized to determine an alternative energy and also minimize environmental pollution. With this current modeling, microalgal-bioethanol utilization mandated with gasoline as well as microalgae cultivation, biofuel production integrated with existing complementary industries, are strongly recommended for future applications. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019