Protein Production Process from a Synthetic Methanotrophic Bacteria Consortium by Using Methane.

Abstract

Microbial origin protein (MOP) is regarded as an alternative to feed and food grade protein, offering a sustainable solution (negligible land footprint and a water footprint 14 times lower than that of soybean) to partially support the increased supply needs. Our goal is to incubate methane-oxidizing bacteria (MOB) by using bubble column bioreactor (BCB) with internal gas recycling. The production process of microbial origin protein consists of 4 steps: (a) fermentation step using a bubble column bioreactor (BCB) with internal gas recycling (polypropylene with a thickness of 11 mm) and working volume of 20 L and column dimension of 11.8 cm as internal diameter (D) and 213.0 cm as height (H), and a H / D ratio of 18.05; (b) biomass harvesting and concentration using centrifugation during 15 min at 3500 rpm and 4°C; (c) High Pressure Homogenization (HPH) processing was used to homogenize the biomass in four passes at pressure levels of 150 MPa with a duration of 4 min between the different passes; and (d) Spray-drying of the biomass using a spray dryer equipped with a rotary atomizer and the atomization pressure was maintained at 0.6 MPa. The methanotrophic biomass obtained exhibited an outstanding nutritional value. More specifically, a high protein content (~62%) along with a balanced amino acids profile, covering all dispensable and non-dispensable AAs, was produced by this process. Moreover, the lipid content (~8%) was also comparable to other nutrient sources such as fishmeal (8%). All the results obtained, and all the parameters determined in the present study are sufficient to implement a bubble column bioreactor at industrial scale and to produce the microbial origin protein (MOP) for animal and human nutrition.