China
Africa
Explore chapters and articles related to this topic
Quorum Sensing and Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Isabel Charlotte Soede, Gerhard Buchbauer
QS inhibition is already used successfully to control membrane fouling by biofilms in water-purification plants. In this area, the most commonly applied method is quorum quenching, meaning the enzymatic degradation of AHLs by using, for instance, purified QQ enzyme obtained from porcine species or bacteria that produce QQ enzymes (Bouayed et al., 2016).
Algal Polysaccharides
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
M Clemente-Carazo, V Sanchez, S Condon-Abanto, Garcia-Vaquero Marco
Filtration techniques seem well suited for initial extraction and purification steps at industrial scale as they can be automated; and permit to treat large volumes of samples (Patel et al. 2013). However, the widespread application of membranes has been hindered due to excessive membrane fouling which could result in reduced performance, severe flux decline, high energy consumption and frequent membrane cleaning or replacement (Feng et al. 2009). Recent studies focused on achieving a better understanding of anti-fouling agents (Feng et al. 2009) and other strategies to reduce fouling. For example the addition of an initial high-molecular weight cut-off membrane before the ultrafiltration step reduces the fouling of the membranes when extracting bacterial oligosaccharides (Mellal et al. 2008).
Microalgal biofouling formation on tubular cellulose-ester membranes during dewatering by forward osmosis
Published in Biofouling, 2023
Salma Karamad Yazdanabad, Yolanda Soriano Jerez, Abdolreza Samimi, Soheila Shokrollahzadeh, Davod Mohebbi-Kalhori, María José Ibáñez González, Tania Mazzuca Sobczuk, Emilio Molina Grima
The properties of the microalgal cells, the membrane surface characteristics, and the draw solution chemistry play important roles in biofouling formation during FO microalgal dewatering. Biofouling can also develop due to the presence of divalent cations (i.e. Ca+2, Mg+2) and its superficial networking attraction to the polymeric substances in the microalgal cell wall, which leads to an increase in interfacial forces on the membrane surface and between the cells (Zou et al. 2013; Larronde-Larretche and Jin 2016). The divalent cations are mainly transferred through the membrane to the feed side (the microalgal suspension) due to the reverse diffusion of salts from the draw agent. Membrane fouling during the initial stage is attributed to foulant-membrane interactions that are later compounded by foulant-adhered foulant interplay (Myat et al. 2014; Meng et al. 2015). The interfacial characteristics of the foulants and the membrane surface have significant effects on the fouling formation properties (Hwang and Chiang 2014; Mollahosseini and Rahimpour 2014). Therefore, an accurate understanding of membrane fouling depends on properly describing the interaction mechanisms acting on the foulant-membrane and within the foulants themselves.
The effect of different carbon sources on biofouling in membrane fouling simulators: microbial community and implications
Published in Biofouling, 2022
Johny Cabrera, Hao-yu Guo, Jia-long Yao, Xiao-mao Wang
Nanofiltration (NF) is being more widely used for the enhanced treatment of micro-polluted source water for the production of drinking water (Kolpin 2002; Liu et al. 2020). The role of NF membranes is becoming more significant as drinking water quality regulations become more rigorous and the desire for higher quality drinking water increases. Nanofiltration is highly effective at removing micropollutants and natural organic matter (NOM) while preserving most of the mineral salts in the treated water (Ventresque et al. 2000; Houari et al. 2013). Membrane fouling is one of the most difficult operating issues that NF must deal with. Membrane fouling is classified into three types: inorganic fouling, organic fouling, and biofouling (Schäfer et al. 2004). Membrane fouling causes a slew of issues, including increased energy use, decreased water flux, and higher channel pressure drops (Flemming 2002, 2020; Dreszer et al. 2013, 2014; DuPont 2020). Biofouling is the most important sort of foulant found in NF systems since it is widespread in membrane systems on the one hand and difficult to control and remove on the other. A membrane fouling simulator (MFS) (Vrouwenvelder et al. 2006, 2007; Farhat et al. 2019) is one of the tools used to investigate biofouling in spiral wound membranes. It measures the pressure drop along the feed channel as an indicator of biofouling.
Developments and opportunities in continuous biopharmaceutical manufacturing
Published in mAbs, 2021
Ohnmar Khanal, Abraham M. Lenhoff
Cell retention may also be accomplished in a separate filtration unit, such as a tangential flow filtration (TFF) device. However, the recirculation of the sample through a peristaltic pump in TFF introduces shear damage and cell lysis.43 This is ameliorated in alternating tangential flow filtration (ATF) (Figure 1a), in which the sample is pumped in alternating directions of flow over the membrane surface using a diaphragm pump. Although ATF is the most popular cell-retention technology, its cellular residence time must be considered in optimizing cell growth and productivity.50 Membrane fouling must also be mitigated, as it decreases membrane permeability and filtrate flow. A continuous microfluidic device has resistance in the retentate flow and uses a variable sample flow rate to flush the membrane periodically.51 The device boasts a small footprint, but requires further optimization, especially at a larger scale.