**1.3 Other value-added products accessible through methane fermentation**

Using natural and engineered strains, not only protein and biopolymers can be obtained from methane, but also several other compounds, for example


For a recent review on bioproducts from methane using methanotrophs, see Ref. [17]. A methanotroph-based 2nd generation biorefinery, that is, single-input, multiple-output configuration is treated in Refs. [23, 27]. In general, multi-product biorefineries are better from an economical point of view for methane-based industrial biomanufacturing. For biorefinery downstream processes, see Refs. [28–30].
