**2.2 PHB production process**

In Ref. [163], the authors carried out a techno-economic assessment of methanotrophic PHB manufacturing, compare **Figure 4**.

The key findings from Ref. [163] for a PHB production on the order of 100,000 t/a by methanotrophic fermentation were:


#### **Figure 4.**

*PFD (process flow diagram) to convert methane into PHB, with mass balance. Source: [163].*

*Value-Added Products from Natural Gas Using Fermentation Processes: Products… DOI: http://dx.doi.org/10.5772/intechopen.104643*

These figures of 3.2–6.8\$/kg of PHB are very promising, as today PHA suffers from high production costs and hence a limited market.
