Biofilm-mediated bioremediation is a powerful tool for the removal of environmental pollutants

Trichosporon species are basidiomycetous, yeast-like organisms capable of filamentous growth, i.e., dimorphic (Fig 1), that are distributed throughout nature [1]. They are important from a biotechnological point of view as they are capable of decontaminating polluted environments by accumulating large amounts of oils [2–5]. A limited number of reports also show their presence in the human microbiome, such as Trichosporon asahii, which has been isolated from human fecal samples, the skin of healthy individuals, and patients with atopic dermatitis [1,6– 10]. In addition, Trichosporon spp. can cause white piedra, hypersensitivity pneumonitis, superficial infections, and invasive trichosporonosis [11]. Designated 150 years ago, the genus Trichosporon was for many years a collection of many different yeast-like organisms. Until the end of the 20th century, a wide range of species were included under the name of Trichosporon beigelii or synonyms, which were later shown to be phylogenetically distinct. With the advent of molecular techniques, the genus was rearranged, and many of its species were reassigned to other genera and new ones were described. Currently there are 51 accepted Trichosporon species, 16 of which have clinical relevance [1,12–13] (these species are highlighted in Fig 2). Formerly associated with uncommon hair and skin infections, research on Trichosporon has fallen behind more life-threatening fungi such as Candida or Cryptococcus species, until the rise of opportunistic, deeply seated, disseminated Trichosporon infections (especially T. asahii) over the last decades. A lack of background knowledge impairs the proper diagnosis and treatment of Trichosporon infections. Fortunately in the recent years, studies of Trichosporon epidemiology [14], virulence factors [15,16], antifungal susceptibility [16,17], and animal models of infection [18,19] have been conducted. There are a few reports of genetic transformation systems for T. cutaneum, which used both dominant and auxotrophic markers [20,21]. However, forward and reverse genetics is still not common practice in the study of Trichosporon. Molecular techniques have already proved necessary for the detection and correct identification of Trichosporon species [1,17]. However, the use of whole genome sequencing and gene manipulation techniques in Trichosporon is in its infancy, in comparison to other fungi, such as Candida or Aspergillus species. Genome sequences for a T. asahii environmental strain and a strain isolated from a progressive psoriatic lesion are available [22,23]. Both T. asahii genomes are of approximately 25 Mbp and are predicted to encode approximately 9,000 genes. A comparison of these two Trichosporon genomes revealed>99% chromosomal and mitochondrial sequence identity. When compared to the genomes of other skin-associated or

On and Under the Skin: Emerging Basidiomycetous Yeast Infections Caused by Trichosporon Species

The release of organic and inorganic pollutants into the environment due to domestic, agricultural, and industrial activities poses serious threats to the environment and public health. The existing conventional wastewater treatment plants are insufficient to remove contaminants altogether and therefore more productive and innovative treatment approaches are being explored widely. Among the emerging biological processes, bacterial biofilm-mediated wastewater treatment has shown many advantages compared with other emerging technologies. Biofilm in various bioremediation systems such as biofilters, aerobic, and anaerobic granular sludge reactors, and rotating disk contractors are being explored for treating wastewaters. However, the development of a robust and reliable biofilm-mediated remediation technology with feasibility for implementation at a massive scale remains challenging. Therefore an in-depth understanding of the biofilm formation processes and specific mechanisms are necessary to improve biofilm-mediated bioremediation. In this chapter we discuss the various aspects such as the nature and role of biofilm for various prospective bioremediations. Various topics related to biofilm formation for applications such as the biofilm life cycle, microbes involved, factors affecting the biofilm formation and biofilm properties, associated extracellular polysaccharide, spatial heterogeneity, and microbial interaction have been discussed with updated information. Besides, the emerging scope and miscellaneous use of biofilms with their adverse impacts on the environment have been discussed. Most of the aspects covered are unique with detailed description of the properties and processes which are likely to help in the improvement and further development of the biofilm-mediated bioremediation.

Recent advances in the application of biofilm in bioremediation of industrial wastewater and organic pollutants

https://link-springer-com-443.webvpn.jmu.edu.cn/content/pdf/10.1007%2F978-3-319-73645-7_137.pdf

Biofilm-Based Systems for Industrial Wastewater Treatment

Oil pollution in marine environment caused by oil spillage has been a main threat to the ecosystem including the ocean life and to the human being. In this research, three indigenous purple photosynthetic strains Rhodopseudomonas sp. DD4, DQ41, and FO2 were isolated from oil-contaminated coastal zones in Vietnam. The cells of these strains were immobilized on different carriers including cinder beads (CB), coconut fiber (CF), and polyurethane foam (PUF) for diesel oil removal from artificial seawater. The mixed biofilm formed by using CB, CF, and PUF as immobilization supports degraded 90, 91, and 95% of diesel oil (DO) with the initial concentration of 17.2 g/L, respectively, after 14 days of incubation. The adsorption of DO on different systems was accountable for the removal of 12–16% hydrocarbons for different carriers. To the best of our knowledge, this is the first report on diesel oil degradation by purple photosynthetic bacterial biofilms on different carriers. Moreover, using carriers attaching purple photosynthetic bacteria to remove diesel oil in large scale is considered as an essential method for the improvement of a cost-effective and efficient bioremediation manner. This study can be a promising approach to eliminate DO from oil-contaminated seawater.

Enhanced Degradation of Diesel Oil by Using Biofilms Formed by Indigenous Purple Photosynthetic Bacteria from Oil-Contaminated Coasts of Vietnam on Different Carriers.

Application of a biofilm formed by a mixture of yeasts isolated in Vietnam to degrade aromatic hydrocarbon polluted wastewater collected from petroleum storage.

Le Phi Nga

Papers

Application of a biofilm formed by a mixture of yeasts isolated in Vietnam to degrade aromatic hydrocarbon polluted wastewater collected from petroleum storage.