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The microbial production of chemicals has traditionally relied on a single engineered microbe to enable the complete bioconversion of substrate to final product. Recently, a growing fraction of research has transitioned towards employing a modular co-culture engineering strategy using multiple microbes growing together to facilitate a divide-and-conquer approach for chemical biosynthesis. Here, we review key success stories that leverage the unique advantages of co-culture engineering, while also addressing the critical concerns that will limit the wide-spread implementation of this technology. Future studies that address the need to monitor and control the population dynamics of each strain module, while maintaining robust flux routes towards a wide range of desired products will lead the efforts to realize the true potential of co-culture engineering., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Curcuminoids (cus) have attracted increasing attention because of the antioxidant, anticancer, and antitumor activities while their production is limited because of its main source, turmeric plant, demonstrates extensive seasonal variation. In this study, we constructed Escherichia coli co-culture system for the rapid production of curcuminoids from glucose. Firstly, the overexpression of curcuminoid synthase and four different strategies related to increasing the intracellular malonyl-CoA pool were conducted in engineered E. coli. We found that bisdemethoxycurcumin (BDMC) is the main product and that high level of malonyl-CoA pool is essential for BDMC production. We also obtained the maximum titer (13.8 mg L -1 ) of BDMC within 4 h by fast preparation directly from p-coumaric acid. Secondly, we developed a process for BDMC synthesis from glucose using a co-culture system where an E. coli strain is used to produce p-coumaric acid from glucose and another E. coli strain converted p-coumaric acid into the final product. Compared to the mono-culture system, the co-culture is more potent and resulted in 6.28 mg L -1 of BDMC from glucose within 22 h of fermentation in a 3-L bioreactor. This is the first time a co-culture method is employed for the production of curcuminoids from glucose in a lab scale bioreactor. This system provides a new method transforming inexpensive substrate into value-added products., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two-dimensional (2D) culture systems do not represent the native microenvironment of the cells which is known to be three dimensional (3D), and surrounded by other cells from all directions. There exist interactions with other cell types in the same vicinity and this also cannot be replicated in a 2D culture. To study the cell-cell interactions between two or more cell types and their biological functions, a few 3D models have been used by different investigators. We have designed a 3D model to investigate the cell-cell interactions between various types of ovarian cells. The same model was also used to study the interactions between prostate cancer epithelial cells and stromal cells. This model uses hydrogel as the anchor matrix to fabricate the constructs and microencapsulation techniques to design multilayered microcapsules. In these multilayer microcapsules the different types of cells are compartmentalized by a sequential encapsulation process. In this chapter, we provide the protocol to compartmentalize two cell types in the same multilayer microcapsules. Although this chapter describes the fabrication of multilayer microcapsules with ovarian cells, the same approach could be applied to other multi-cell tissue-engineered constructs that require cell-cell interactions.