http://synbioproject.tech/cpi/applications/biobutanol/
As a fuel or gasoline additive, biobutanol has many advantages over ethanol, including drop-in capability, higher energy content and better transport and handling properties. In addition, butanol can also be used as a building block for chemical manufacturing. Source
This technology overcomes toxic and inhibitory effects on butanol-producing microorganisms, a major bottleneck in scaling existing biobutanol processes. Based on preliminary investigations, Microvi’s technology has shown substantial increases in the titer of butanol over its solubility limit. Microvi’s technology is also expected to provide economic advantages such as reduced water usage, waste production and energy use. Biobutanol processes using Microvi’s technology would benefit from reduced capital and operating costs. The technology will be retrofitable in existing bioethanol processes and work with any microorganism including genetically modified organisms. Source