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The purple strains of bacteria are an interesting group belonging to the family of Rhodospirillaceae. In this group, we find Rhodopseudomonas (Rp.) palustris, which is known for its ability to produce a clean fuel as H2 [1], a polymer as poly-?-hydroxybutyrate (PHB) [2], a bioactive substance as cis-vaccenic acid (antivirus) [3, 4] and carotenoid type as lycopene [5]. Rhodopseudomonas biomasses are rich in proteins (from 51 to 61 % of dry weight) and they can be used very well as feed stock supplements (Vrati 1984). The underwater tubular photobioreactor (UwTP) is a fully controlled outdoor system for the study of photosynthetic bacteria under anaerobic conditions [2]. We used a 53 L-reactor volume with high performances to investigate on Rhodopseudomonas palustris growth. The growth kinetics of Rhodopseudomonas cells was investigated under a natural light-dark cycle (from sunrise to sunset) and under a forced light-dark cycle (10L/14D). Relationships among solar radiation (SR), biomass output rate (BOR) and growth rate (?) were investigated. After determining the elemental biomass molar composition and its combustion heat, some trends of photosynthetic efficiency (PE) were obtained over daylight. The PE trends always were of oscillatory type, with the exception of that achieved at low biomass concentration. The reason why Rp. cells exhibited this growth behavior was not clear and further studies are in progress. Under a natural light/dark cycle the maximum value of PE was 11.2% at sunset; under a forced light cycle (10L/14D) the highest PE of 8.5% was achieved in the morning. Three initial biomass concentrations were investigated (0.65 g l-1; 1.01 g l-1 and 1.54 g l-1). When the initial biomass concentration was optimal (1.01 g l-1), over the period 11:30 - 13:00, we achieved the highest reactor output rate of 9.91 g (dw) R-1 h-1 and the growth rate reached its maximum value of 0.121 h-1. In the past, the primary goal of photosynthetic microorganism mass-culture systems was to maximize the production of biomass; the second and often equally important goal was to optimize the production of specific biochemicals [6]. Nowadays, optimization of the production of specific biochemicals is surely the most important goal. By scaling up the photobioreactor we can produce biomasses as potential sources of livestock and fish feed. Alternatively, we could produce a specific bioactive substance (cis-vaccenic acid), a thermoplastic polymer (PHB) or a biofuel (H2), which can be more economically successful than biomasses for animal feed.

Background and aim of the work: complications in surgical wound healing represent the main postoperative complication in ankle and distal tibia fractures. Whereas the use of Incisional Negative Pressure Wound Therapy (INPWT) is recognized to have a role in wound complications prevention in prosthetic surgery, literature about its use in trauma surgery is scarce. The aim of this study was to compare the effectiveness of IN-WPT with a conventional dressing in order to prevent surgical wound complications in ankle and distal tibia fractures. Methods: The study population included patients over 65 years as well as patients under 65 years considered at risk for wound complications (smokers, obese, affected by diabetes), who underwent ORIF for bi/tri-malleolar ankle fractures or distal tibia (pilon) fractures. After surgery, patients were randomized to receive a conventional dressing or INPWT. Complications in surgical wound healing were classified in major (requiring surgical intervention) and minor complications. Results: 65 patients were included in the study. The rate of minor and major complications between the two groups was not significantly different, although a positive trend towards a lower minor complications rate was noted in the INPWT group (12.6% vs 34.7%). No complications or complaints were reported for the INPWT device. Conclusions: INPWT proved to be safe, well-tolerated and showed promising results in preventing surgical wound complications in ankle and distal tibia fractures.