Category Archives: Michael Winn

Characterisation of spin coated engineered Escherichia coli biofilms using atomic force microscopy

Andreas N. Tsoligkas ; James Bowen ; Michael Winn ; Rebecca J. M. Goss ; Tim W. Overton ; Mark J. H. Simmons

Colloids and Surfaces B: Biointerfaces 2012, 89 152-160

The ability of biofilms to withstand chemical and physical extremes gives them the potential to be developed as robust biocatalysts. Critical to this issue is their capacity to withstand the physical environment within a bioreactor; in order to assess this capability knowledge of their surface properties and adhesive strength is required. Novel atomic force microscopy experiments conducted under growth conditions (30 °C) were used to characterise Escherichia coli biofilms, which were generated by a recently developed spin-coating method onto a poly-l-lysine coated glass substrate. High-resolution topographical images were obtained throughout the course of biofilm development, quantifying the tip–cell interaction force during the 10 day maturation process. Strikingly, the adhesion force between the Si AFM tip and the biofilm surface increased from 0.8 nN to 40 nN within 3 days. This was most likely due to the production of extracellular polymer substance (EPS), over the maturation period, which was also observed by electron microscopy. At later stages of maturation, multiple retraction events were also identified corresponding to biofilm surface features thought to be EPS components. The spin coated biofilms were shown to have stronger surface adhesion than an equivalent conventionally grown biofilm on the same glass substrate.

Biofilms and their engineered counterparts: A new generation of immobilised biocatalysts

Michael Winn ; Joanne M. Foulkes ; Stefano Perni ; Mark J. H. Simmons ; Tim W. Overton ; Rebecca J. M. Goss

Cat Sci Tech 2012, 2 1544-1547

The robust nature of biofilms makes them medicinally difficult to treat, however this same property renders them an attractive method for protecting and immobilising enzymes for biotransformation. Although biofilms consisting of a consortium of different microbial species have been routinely used in water purification for many decades, there are few reported examples of single species biofilms being harnessed for industrial applications. The potential of using tailored single species biofilms in order to catalyse a biotransformation of choice is attractive; we reflect upon recent advances in the use and generation of such platforms, from both biological and process engineering viewpoints.

Graphical abstract: Biofilms and their engineered counterparts: A new generation of immobilised biocatalysts

Engineering Biofilms for Biocatalysis

Andreas N. Tsoligkas ; Michael Winn ; James Bowen ; Tim W. Overton ; Mark J. H. Simmons ; Rebecca J. M. Goss

ChemBioChem 2011, 12 (9) 1391-1395

Biofilm, friend not foe: Single species biofilms can be engineered to form robust biocatalysts with greater catalytic activity and significantly improved catalytic longevity than purified and immobilised enzymes. We report the engineering, structural analysis and biocatalytic capability of a biofilm that can mediate the conversion of serine and haloindoles to halotryptophans.

Antimicrobial nucleoside antibiotics targeting cell wall assembly: Recent advances in structure-function studies and nucleoside biosynthesis

Michael Winn ; Rebecca J. M. Goss ; Ken-ichi Kimura ; Timothy D. H. Bugg

Nat Prod Rep 2010, 27 279-304

The quest for new antibiotics, especially those with activity against Gram-negative bacteria, is urgent; however, very few new antibiotics have been marketed in the last 40 years, with this limited number falling into only four new structural classes. Several nucleoside natural product antibiotics target bacterial translocase MraY, involved in the lipid-linked cycle of peptidoglycan biosynthesis, and fungal chitin synthase. Biosynthetic studies on the nikkomycin, caprazamycin and pacidamycin/
mureidomycin families are also reviewed.

A convenient one-step synthesis of L-aminotryptophans and improved synthesis of 5-fluorotryptophan

Michael Winn ; Abhijeet Deb Roy ; Sabine Grüschow ; Raj S. Parameswaran ; Rebecca J. M. Goss

Bioorg Med Chem Lett 2008, 18 (16) 4508-4510

A one-pot biotransformation for the generation of a series of l-aminotryptophans using a readily prepared protein extract containing tryptophan synthase is reported. The extract exhibits remarkable stability upon freeze-drying, and may be stored and used for long periods after its preparation without significant loss of activity.