Bio-Mitigation of Carbon Dioxide Using Desmodesmus sp. in the Custom-Designed Pilot-Scale Loop Photobioreactor

Abstract

Today’s society is faced with many upfront challenges such as the energy crisis, water pollution, air pollution, and global warming. The greenhouse gases (GHGs) responsible for global warming include carbon dioxide (CO2), methane (CH4), nitrous oxide (NOx), water vapor (H2O), and fluorinated gases. A fraction of the increased emissions of CO2 in the atmosphere is due to agricultural and municipal solid waste (MSW) management systems. There is a need for a sustainable solution which can degrade the pollutants and provide a technology-based solution. Hence, the present work deals with the custom design of a loop photobioreactor with 34 L of total volume used to handle different inlet CO2 concentrations (0.03%, 5%, and 10% (v/v)). The obtained values of biomass productivity and CO2 fixation rate include 0.185 ± 0.004 g L−1 d−1 and 0.333 ± 0.004 g L−1 d−1, respectively, at 10% (v/v) CO2 concentration and 0.084 ± 0.003 g L−1 d−1 and 0.155 ± 0.003 g L−1 d−1, respectively, at 5% (v/v) CO2 concentration. The biochemical compositions, such as carbohydrate, proteins, and lipid content, were estimated in the algal biomass produced from CO2 mitigation studies. The maximum carbohydrate, proteins, and lipid content were obtained as 20.7 ± 2.4%, 32.2 ± 2.5%, and 42 ± 1.0%, respectively, at 10% (v/v) CO2 concentration. Chlorophyll (Chl) a and b were determined in algal biomass as an algal physiological response. The results obtained in the present study are compared with the previous studies reported in the literature, which indicated the feasibility of the scale-up of the process for the source reduction of CO2 generated from waste management systems without significant change in productivity. The present work emphasizes the cross-disciplinary approach for the development of bio-mitigation of CO2 in the loop photobioreactor.

Development of a Greenhouse Wastewater Stream Utilization System for On-Site Microalgae-Based Biostimulant Production

“…was investigated under varying CO2 concentrations (0.03%, 5%, and 10% v/v) within a smallscale photobioreactor loop. The results of our study revealed a prolonged lag phase of approximately 20 days prior to CO2 introduction into the loop, contrasting with the brief lag phase of 1 to 3 days reported in the study by Anand et al [37]. Despite this disparity, both studies showcased a sustained increase in microalgae growth during the exponential phase over 14 days following the introduction of CO2.…”

“…This growth trend, observed in both dry biomass and optical density, was attributed to optimal nutrient levels conducive to cell proliferation within the reactor. However, the differences between the two studies can be attributed to the significantly lower volume of the PBR loop used in our study, approximately 1000 L compared to the 34 L volume used by Anand et al [37]. Consequently, the extended lag phase observed in our study prior to CO2 introduction is primarily attributed to the larger volume of the PBR, requiring additional time for proper solution mixing during inoculation, resulting in lower initial dry biomass levels.…”

“…Moreover, in a recent study [37], the growth performance of Desmodesmus sp. was investigated under varying CO2 concentrations (0.03%, 5%, and 10% v/v) within a smallscale photobioreactor loop.…”

Current Advancements in Biofuel Production from Microalgae: Harvesting and Conversion Technologies

“…The biomass yields of various microalgae using open systems and PBRs is mentioned in Tab. 1 [38][39][40][43][44][45][46][47][48][49][50][51][52].…”