Using α–Amylase from Bacillus subtilis as a Catalyst for the Production of Sweet Potato Biofuels.

Floyd L. Inman, III; Heather Walters*; Len Holmes

Bacillus subtilis is an aerobic, Gram-positive, endospore-forming bacterium that has the ability to produce and secrete the hydrolyzing carbohydrate enzyme, α-amylase. α–Amylase is an enzyme that is used in various industries to rapidly degrade complex polysaccharides (e.g. starches) into smaller oligosaccharides. α–Amylase from B. subtilis is currently being investigated as a potential source for producing fermentable sugars from the remnants of sweet potatoes. These fermentable sugars will be bioconverted into ethanol as a source for biofuels. B. subtilis was cultured in a 2 L Sartorius-stedim Biostat ® A+ Plus fermentation system. An optical density probe was used to measure bacterial growth within the culture. α–Amylase activity was assayed throughout the culturing period to determine the time-frame of maximum α–amylase production. Enzyme production was stimulated 5-fold and higher by the addition of high concentrations of starches.

Wireless Control of Fed-Batch Fermentation Systems.

Heather Walters*, Eric Moreau, Sunita Singh, Floyd L. Inman, III, Len D. Holmes

Bioreactor operation requires continuous monitoring of fermentation parameters and real-time control over bioreactor devices.  Remote monitoring and control of the bioreactor's computer via the Internet avoids the necessity of personnel being continually on-site during operation.  A Sartorius Biostat A Plus® bioreactor (2 Liter) and its computer control system were interfaced with the commercial software GoToMyPC®. The bioreactor was equipped with all controls for monitoring during experiments:  oxygen sensor, pH sensor, temperature sensor and agitation. Other calibrations (media inflow & outflow, antifoam additions) were calibrated with the system’s peristaltic pump adjusted for time.  Remotely controlled night-vision web cameras allowed monitoring capability of the glass fermentation vessel.  A Wi-Fi connection via wireless router allowed multiple system connections to the host computer.  The window screen of the main computer can be accessed from any wireless device with an Internet connection. The secured Internet Protocol (IP) address assures that the system can only be controlled by the main users. This wireless interface permits the remote control of fed-batch fermentations and other culturing protocols.