1014 Fig. 2 Schematic overview of the expression process from induction all the way to secretion of the light of troubleshooting during a metagenomic library screening Appl Microbiol Biotechnol (2012) 93:1005–1020 One obvious strategy would be to scale up functional screenings by the use of multiple hosts and screening methods in parallel (e.g. Craig et al. 2010). This enables one to increase the chance to successfully express and detect inserted genes. However, to prevent such an experiment to become costly and time-consuming, high-throughput, potentially microfluidic, technologies are required. This might be combined with cell lysis procedures, either chemically or by the use of an autolytic vector, to minimize biases by enzymatic breakdown of the gene product, toxicity or secretion problems.