RESUMEN
Currently, researchers have focused on electrokinetic (EK) bioremediation due to its potential to remove a wide-range of pollutants. Further, to improve their performance, synthetic surfactants are employed as effective additives because of their excellent solubility and mobility. Synthetic surfactants have an excessive position in industries since they are well-established, cheap, and easily available. Nevertheless, these surfactants have adverse environmental effects and could be detrimental to aquatic and terrestrial life. Owing to social and environmental awareness, there is a rising demand for bio-based surfactants in the global market, from environmental sustainability to public health, because of their excellent surface and interfacial activity, higher and stable emulsifying property, biodegradability, non- or low toxicity, better selectivity and specificity at extreme environmental conditions. Unfortunately, challenges to biosurfactants, like expensive raw materials, low yields, and purification processes, hinder their applicability to large-scale. To date, extensive research has already been conducted for production scale-up using multidisciplinary approaches. However, it is still essential to research and develop high-yielding bacteria for bioproduction through traditional and biotechnological advances to reduce production costs. Herein, this review evaluates the recent progress made on microbial-surfactants for bioproduction scale-up and provides detailed information on traditional and advanced genetic engineering approaches for cost-effective bioproduction. Furthermore, this study emphasized the role of electrokinetic (EK) bioremediation and discussed the application of BioS-mediated EK for various pollutants remediation.
Asunto(s)
Contaminantes Ambientales , Restauración y Remediación Ambiental , Contaminantes del Suelo , Tensoactivos , Contaminantes del Suelo/análisis , Biodegradación Ambiental , BacteriasRESUMEN
Microbubble formulations have a long history for enhancement of ultrasound (US) imaging and recently also for therapeutic applications. Previously, a series of freeze-dried bubble formulations based on the lipids DSPC and DSPG were developed. Here, we have attempted to scale-up the production process for future more extensive studies. Bubbles were prepared by homogenization of a lipid dispersion in a perfluoropropane atmosphere in a medium size (300-500 mL) homogenizer and then freeze-dried for better storage stability. In total, 300 freeze-dried vials were prepared. The properties of the bubbles were similar to those previously prepared on a lab scale with the difference that they were slightly larger and also had a better stability. The re-entrapped gas concentration after re-constituted freeze-dried bubbles was 9.4 µL/µmol lipid. The re-entrapped rate was 72.3% of fresh bubble before freeze-drying (13.0 µL/µmol lipid). The half-life of US imaging signal of the re-constituted freeze-dried bubbles in water in vitro was shorter than that of the fresh bubbles (2.7 min vs. 3.3 min). A leak of Evans Blue, that binds to albumin, from mouse ear blood vessel was observed after combination of bubble and US irradiation of 1 MHz for 1 min. As a result of bubble vibration by US irradiation, vascular endothelial cell bond opened and Evans Blue leaked. Toxicity of bubble was tested in rats. No toxicity was found after a single injection in the dose range tested. No serious toxicity was seen after repeated injections (one daily injection during 15 days).