A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.

Effect of Temperature

Overview of microalgal extracellular polymeric substances (EPS) and their applications.

In drinking water distribution systems (DWDS), biofilms are the predominant mode of microbial growth, with the presence of extracellular polymeric substance (EPS) protecting the biomass from environmental and shear stresses. Biofilm formation poses a significant problem to the drinking water industry as a potential source of bacterial contamination, including pathogens, and, in many cases, also affecting the taste and odor of drinking water and promoting the corrosion of pipes. This article critically reviews important research findings on biofilm growth in DWDS, examining the factors affecting their formation and characteristics as well as the various technologies to characterize and monitor and, ultimately, to control their growth. Research indicates that temperature fluctuations potentially affect not only the initial bacteria-to-surface attachment but also the growth rates of biofilms. For the latter, the effect is unique for each type of biofilm-forming bacteria; ammonia-oxidizing bacteria, for examp...

/pdf/understanding-monitoring-and-controlling-biofilm-growth-in-5ez2rie58i.pdf

Understanding, Monitoring, and Controlling Biofilm Growth in Drinking Water Distribution Systems

Widespread application of algal biofilm-based systems in wastewater treatment has been limited despite the potential benefits of a low cost nutrient removal option and a source of biomass for bioproduct production. The performance and processes involved with algal biofilm-based systems in wastewater treatment are not adequately addressed in the available literature, which hinders design and scale up of effective systems for applications to municipal, industrial, and agricultural waste streams. A critical review is presented, which examines nutrient removal trends, biomass productivity, growth requirements, and challenges for algal biofilm-based biotechnology as applied to wastewater treatment both at bench scale and at pilot scale operations. Information on algal biofilms in natural environments derived from ecology and limnology disciplines was utilized in areas of limited research with regard to wastewater treatment. This critical review identified key areas that need to be addressed for designing, building, and testing algal biofilm-based technologies that integrate both nutrient removal from wastewater and enhanced biomass production to improve the performance of engineered systems. The review identifies the need for research on factors that affect algal growth, mass transport, species selection, algal–bacterial interactions, and validation of laboratory research in field scale tests for the development of an algal biofilm based technology platform for integrating wastewater treatment and biomass production.

Algal biofilm based technology for wastewater treatment

Activated sludge bulking and foaming control

Aims: This work reports on one of the first attempts to use biofilm-forming cyanobacteria for biomass and lipid production. Methods and Results: Three isolates of filamentous cyanobacteria were obtained from biofilms at different Italian sites and characterized by a polyphasic approach, involving microscopic observations, ecology and genetic diversity (studying the 16S rRNA gene). The isolates were grown in batch systems and in a semi-continuous flow incubator, specifically designed for biofilms development. Culture system affected biomass and lipid production, but did not influence the fatty acid profile. The composition of fatty acids was mainly palmitic acid (>50%) and less amounts of other saturated and monounsaturated fatty acids. Only two isolates contained two polyunsaturated fatty acids. Conclusions: Data obtained from the flow-lane incubator system would support a more economical and sustainable use of the benthic microorganisms for biomass production. The produced lipids contained fatty acids suitable for a high-quality biodiesel production, showing high proportions of saturated and monounsaturated fatty acids. Significance and Impact of the Study: Data seem promising when taking into account the savings in cost and time derived from easy procedures for biomass harvesting, especially when being able to obtain the co-production of other valuable by-products.

https://sfamjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.2012.05416.x

Characterization of biofilm‐forming cyanobacteria for biomass and lipid production

Biofilm growth and control in cooling water industrial systems.

Phototrophic biofilm samples from an Italian wastewater treatment plant were studied in microcosm experiments under varying irradiances, temperatures and flow regimes to assess the effects of environmental variables and phototrophic biomass on capsular exopolysaccharides (CPS). The results, obtained from circular dichroism spectroscopy and High Performance Liquid Chromatography, suggest that CPS have a stable spatial conformation and a complex monosaccharide composition. The total amount present was positively correlated with the biomass of cyanobacteria and diatoms, and negatively with the biovolume of green algae. The proportion of uronic acids showed the same correlation with these taxon groups, indicating a potential role of cyanobacteria and diatoms in the removal of residual nutrients and noxious cations in wastewater treatment. While overall biofilm growth was limited by low irradiance, high temperature (30 degrees C) and low flow velocity (25 l h(-1)) yielded the highest phototrophic biomass, the largest amount of CPS produced, and the highest proportion of carboxylic acids present.

/pdf/capsular-polysaccharides-of-cultured-phototrophic-biofilms-48xqa83tvr.pdf

Capsular polysaccharides of cultured phototrophic biofilms

Marine hydrocarbon-degrading bacteria breakdown poly(ethylene terephthalate) (PET)

In this study, next generation sequencing and catalyzed reporter deposition fluorescence in situ hybridization, combined with confocal microscopy, were used to provide insights into the biodiversity and structure of biofilms collected from four full-scale European cooling systems. Water samples were also analyzed to evaluate the impact of suspended microbes on biofilm formation. A common core microbiome, containing members of the families Sphingomonadaceae, Comamonadaceae and Hyphomicrobiaceae, was found in all four biofilms, despite the water of each coming from different sources (river and groundwater). This suggests that selection of the pioneer community was influenced by abiotic factors (temperature, pH) and tolerances to biocides. Members of the Sphingomonadaceae were assumed to play a key role in initial biofilm formation. Subsequent biofilm development was driven primarily by light availability, since biofilms were dominated by phototrophs in the two studied 'open' systems. Their interactions with other microbial populations then shaped the structure of the mature biofilm communities analyzed.

F Di Pippo

Papers

Characterization of biofilm‐forming cyanobacteria for biomass and lipid production

Biofilm growth and control in cooling water industrial systems.

Capsular polysaccharides of cultured phototrophic biofilms

Marine hydrocarbon-degrading bacteria breakdown poly(ethylene terephthalate) (PET)

Unravelling the core microbiome of biofilms in cooling tower systems.