An attributional life cycle assessment of microbial protein production: A case study on using hydrogen-oxidizing bacteria

From renewable energy to sustainable protein sources: Advancement, challenges, and future roadmaps

“…However, 2nd generation MP using MOB pathways has not been scaled-up and thus the environmental impacts at industrial scale have not been scrutinized so far. Furthermore, only limited studies have investigated HOB-based 2nd generation MP at pilot scale from LCA points of view [22,29]. The literature review shows the lack of deep investigation on sustainability aspects of both MOB and HOB production facilities, especially under the integrated system with anaerobic digestion plants and the associated nutrient recovery and biogas processing facilities.…”

“…Having compared 2nd generation HOB and 1st generation MOB production, HOB route using renewables showed lower impacts than MOB route, even if MOB production facility substituted natural gas with biogas [22,29,44]. As shown by Sillman et al [29], HOB production pathway under the best-case scenario, which uses wind or solar energy, could have 53% and 42% lower global warming potential (GWP) than MOB pathway using renewables and biogas, respectively.…”

“…They showed waster scarcity had a high uncertainty and ranged between 0.14 and 0.37 m kg − 1 final product with 65% protein. Moreover, they concluded that when electricity has a hydropower origin, water scarcity of MP sharply increases [22]. The water consumption of FeedKind protein, i.e., commercialized 1st generation MP, is reportedly 10-29 L water.…”

“…Järviö et al [22] studied the environmental impacts of a HOB-based pilot-scale facility using renewable energy without state-of-the-art technologies. They reported 8% lower GWP impact from HOB pathway compared with MOB production based on renewables.…”

“…In the 1980s, scientists made efforts to produce high-quality protein-rich microorganisms which can be used as food/feed ingredient, named MP [17]. Among different types of MP (i.e., algae, yeast, bacteria, and fungi), bacterial-based MP such as methane-oxidizing bacteria (MOB) [18][19][20][21] and hydrogen-oxidizing bacteria (HOB) [22][23][24][25][26] have gained more interest because of their high protein content, digestibility, and amino acid profile comparable with conventional proteins like soybean meal [14,15,27]. The low growth rate and low protein content of fungi and yeast-based protein sources, non-digestible cellulosic cell wall as well as concentrate heavy metals of algae, and high nucleic acid content and low density of bacteria gave them low popularity as future protein sources compared to MP [20,28].…”