In this issue

Biosensors: Combining bio and nano

Song and Park, Biotechnol. J. 2011, 6, 1310–1316.

A biosensor is defined as a sensing device that is composed of a non-biological sensor element and a biological recognition element, e.g., enzymes, antibodies, aptamers or receptor molecules. The specific biomolecule interaction or biochemical reaction of the target molecule is then measured by the sensor element, which elicits an electrical signal. Recent advances in nanotechnology have generated many new opportunities for the development of improved sensing devices, which can be applied in the food and beverage industry, clinical diagnosis, anti-terrorism applications and environmental monitoring. In this issue, Hyun Seok Song and Tai Hyun Park from Seoul, Korea, discuss recent advances and remaining challenges in the development of biosensors through the integration of biomolecules with nanotechnology.

original image 10.1002/biot.201100006

Global regulators of E. coli metabolism

Matsuoka and Shimizu, Biotechnol. J. 2011, 6, 1330–1341.

The ultimate goal of systems biology is the programming of a virtual cell for the prediction of metabolic changes in response to changes in the culture environment and or inactivation of a specific gene. This will help designing cells for more efficient production of a specific metabolite without the need for many experiments. Quantitative modeling for regulatory mechanisms is critical for efficient metabolic engineering. To achieve this, it is important to properly understand the metabolic regulation mechanism and to develop a robust model by incorporating gene-level regulation into the enzymatic reaction model. The metabolic regulation in response to the change in culture environment however, is not well understood. In this issue, Yu Matsuoka and Kazuyuki Shimizu from Japan, review how culture environment affects cell metabolism via global regulators.

original image 10.1002/biot.201000447

Bottlenecks in microbial butanol production

Gu et al., Biotechnol. J. 2011, 6, 1348–1357.

Butanol is not only an important bulk chemical, but also a promising next generation bio-fuel; however, compared to petrochemical-derived production, fermentative butanol production is still not economically competitive. The major drawbacks are the high cost of feedstocks, low butanol concentration in the fermentation broth and the co-production of low-value by-products, i.e., acetone and ethanol. Ideally, one would redirect the entire carbon flow to exclusive butanol production. Although new engineering tools for the manipulation of commonly used Clostridium strains are becoming available, the complex metabolic network of these organisms remains a challenge. In this issue, Weihong Jiang, Sheng Yang et al., from Shanghai and Beijing, China, analyze the main bottlenecks in microbial butanol production and focus on strain engineering strategies to improve feedstock utilization, butanol ratio and titer.

original image 10.1002/biot.201100046