• Energy Research

This study aimed to optimize significant medium nutrient parameters for maximization of algal lipid and biomass production by using multi objective optimization strategy. Nutrients (nitrate, phosphate and carbohydrate) were investigated to improve the lipid accumulation, biomass production and carbohydrate consumption individually and cumulative manner using a central composite design for the Chlorella pyrenoidosa NCIM 2738 cultivation. Maximum lipid, algal biomass and carbohydrate utilization for individual response optimization were found 34.8% (w/w), 1464.3mgL(-1) and 93.4%, respectively at different optimum level of selected parameters. Whereas, maximum lipid accumulation, biomass production and glucose consumption values in multi-response optimization were observed 28.9%, 1271.2mgL(-1) and 89.2%, respectively at optimum level of 16.8mM NaNO3, 300.9μM K2HPO4 and 2.6% (w/v) glucose. The overall enhancements in lipid productivities by single and multi-response optimization in comparison with control medium conditions were found 2.35 and 2.90-fold with productivity level of 24.8 and 30.6mgL(-1)day(-1), respectively.

This study aimed to optimize significant medium nutrient parameters for maximization of algal lipid and biomass production by using multi objective optimization strategy. Nutrients (nitrate, phosphate and carbohydrate) were investigated to improve the lipid accumulation, biomass production and carbohydrate consumption individually and cumulative manner using a central composite design for the Chlorella pyrenoidosa NCIM 2738 cultivation. Maximum lipid, algal biomass and carbohydrate utilization for individual response optimization were found 34.8% (w/w), 1464.3mgL(-1) and 93.4%, respectively at different optimum level of selected parameters. Whereas, maximum lipid accumulation, biomass production and glucose consumption values in multi-response optimization were observed 28.9%, 1271.2mgL(-1) and 89.2%, respectively at optimum level of 16.8mM NaNO3, 300.9μM K2HPO4 and 2.6% (w/v) glucose. The overall enhancements in lipid productivities by single and multi-response optimization in comparison with control medium conditions were found 2.35 and 2.90-fold with productivity level of 24.8 and 30.6mgL(-1)day(-1), respectively.

Abstract Combined process development for efficient recycling of nutrients using microalgae may deliver realistic answer to both environment management and energy generation. This study demonstrates the biomass and lipid yields of Scenedesmus sp. ASK22 and simultaneous nutrient remediation of simulated dairy effluent (SDE). The Plackett-Burman method is employed to screen essential nutrients that effect the Scenedesmus sp. ASK22 lipid production grown in SDE. Central composite design (CCD) is employed to evaluate the interactive effect and optimization of variable. The significant variables are observed to be NaNO3, EDTA, micronutrients and initial pH and these variables are screened on the basis of high confidence levels (p

Abstract Combined process development for efficient recycling of nutrients using microalgae may deliver realistic answer to both environment management and energy generation. This study demonstrates the biomass and lipid yields of Scenedesmus sp. ASK22 and simultaneous nutrient remediation of simulated dairy effluent (SDE). The Plackett-Burman method is employed to screen essential nutrients that effect the Scenedesmus sp. ASK22 lipid production grown in SDE. Central composite design (CCD) is employed to evaluate the interactive effect and optimization of variable. The significant variables are observed to be NaNO3, EDTA, micronutrients and initial pH and these variables are screened on the basis of high confidence levels (p

There is growing interest in recent times for microalgae as a sustainable energy source. However, efficient harvesting of microalgal biomass for various industrial applications is still considered a bottleneck. The present study attempts to evaluate microalgae Scenedesmus sp. harvesting using electro-coagulation-flocculation (ECF). Plackett-Burman design was exploited to explore the significant process parameters, whereas Taguchi's array design was employed for optimization. The optimal conditions were optimized as initial pH 5.0, electrolysis time 15 min, electrode distance 2 cm, sedimentation time 60 min, and current density 12 mA cm-2 for complete harvesting. Under optimum conditions, the energy utilization and the operation cost of ECF process was estimated to be 2.65 kWh kg-1 and USD 0.29 kg-1, respectively. Thus, ECF-based microalgae harvesting was found as a low-cost technique. In addition, neutralizing pH and supplementing macro- and micronutrients enabled the flocculated medium to maintain an approximate growth yield in algal cultivation to that of the fresh BG11 medium. ECF did not affect the amount of microalgal lipids (28.6 ± 1.2, % wt.), chlorophyll a (8.3 ± 0.3 μg mL-1), and fatty acid methyl ester composition (C15:0, C16:0, C17:0, and C18:0) as well. These results strongly recommend ECF as the most appropriate and promising method for harvesting Scenedesmus sp. for biofuel production.

There is growing interest in recent times for microalgae as a sustainable energy source. However, efficient harvesting of microalgal biomass for various industrial applications is still considered a bottleneck. The present study attempts to evaluate microalgae Scenedesmus sp. harvesting using electro-coagulation-flocculation (ECF). Plackett-Burman design was exploited to explore the significant process parameters, whereas Taguchi's array design was employed for optimization. The optimal conditions were optimized as initial pH 5.0, electrolysis time 15 min, electrode distance 2 cm, sedimentation time 60 min, and current density 12 mA cm-2 for complete harvesting. Under optimum conditions, the energy utilization and the operation cost of ECF process was estimated to be 2.65 kWh kg-1 and USD 0.29 kg-1, respectively. Thus, ECF-based microalgae harvesting was found as a low-cost technique. In addition, neutralizing pH and supplementing macro- and micronutrients enabled the flocculated medium to maintain an approximate growth yield in algal cultivation to that of the fresh BG11 medium. ECF did not affect the amount of microalgal lipids (28.6 ± 1.2, % wt.), chlorophyll a (8.3 ± 0.3 μg mL-1), and fatty acid methyl ester composition (C15:0, C16:0, C17:0, and C18:0) as well. These results strongly recommend ECF as the most appropriate and promising method for harvesting Scenedesmus sp. for biofuel production.

Abstract In this study, we sought to improve medium composition for enhanced biomass, lipid and starch content by using response surface methodology and composite desirability function approach for the heterotrophic cultivation of Scenedesmus sp. ASK22. Maximum biomass yield observed was 5.02 ± 0.1 g L-1 and 4.67 ± 0.12 g L-1 for individual and multi-response respectively. Lipid and starch accumulation for individual response and multi-response were found to be 30.72 ± 0.23 (% wt.) and 37.10 ± 2.71 (% wt.) and 29.46 ± 0.17 (% wt.) and 31.06 ± 0.17 (% wt.) respectively. The Lipid and starch productivity in BG11 medium increased to 13.38 and 28.59-fold for individual optimized conditions and 18.20 and 31.97-fold for multi-response optimized conditions respectively. These results propose Scenedesmus sp. ASK22 strain to be a potential candidate for bio-fuel production.

Abstract In this study, we sought to improve medium composition for enhanced biomass, lipid and starch content by using response surface methodology and composite desirability function approach for the heterotrophic cultivation of Scenedesmus sp. ASK22. Maximum biomass yield observed was 5.02 ± 0.1 g L-1 and 4.67 ± 0.12 g L-1 for individual and multi-response respectively. Lipid and starch accumulation for individual response and multi-response were found to be 30.72 ± 0.23 (% wt.) and 37.10 ± 2.71 (% wt.) and 29.46 ± 0.17 (% wt.) and 31.06 ± 0.17 (% wt.) respectively. The Lipid and starch productivity in BG11 medium increased to 13.38 and 28.59-fold for individual optimized conditions and 18.20 and 31.97-fold for multi-response optimized conditions respectively. These results propose Scenedesmus sp. ASK22 strain to be a potential candidate for bio-fuel production.

In this study, the indigenous native microalgae were isolated from domestic and dairy effluent (DE) and further screened for DE treatment and lipid accumulation. All the isolated microalgae were examined for their growth adaptability in DE. The growth parameters of 15 isolates were determined and the following six isolates further selected for comprehensive analysis and identified as Desmodesmus sp. ASK01, Chlorella sp. ASK14, Scenedesmus sp. ASK16, Scenedesmus sp. ASK22, Chlorella sp. ASK25 and Chlorella sp. ASK27. The nutrient remediation capacity of six isolates as well as its lipid accumulation potential and biomass composition were determined. The Scenedesmus sp. ASK22 showed the best combined results and promising strain for the DE treatment and biofuel production. Biomass composition of Scenedesmus sp. ASK22 showed an oil accumulation of 30.7% (w/w) and biomass yield 1.22 g L-1. The fatty acid methyl ester (FAME) mainly composed of C15:0, C16:0, C18:0, C18:1 and C18:3.