Keywords

1 Introduction

Marine extremophiles are the organisms that can thrive and reproduce at extremes of salt concentrations (salinity >1.0 M NaCl), pH (>8.0, <5.0), temperature (1–15 °C, >45 °C), and pressure (average 380 atmosphere, >500–1200 atmosphere and beyond), in the presence of high radiations, recalcitrant compounds, heavy metals, and inhibitors. Extremophiles belonging to the Eubacteria, Archaea, and eukaryotic kingdoms produce extremophilic biomass in ecological niches such as oceans, salt marshes, solar salterns, hypersaline lakes, hot springs, marine hydrothermal vents, and soda lakes. These marine polyextremophiles have great importance and contributed a lot in biotechnological industries. The bioactive compounds such as extremozymes, proteins, and extremolytes are exploited in various bioprocesses and industries. But, it remains to uncover their potential biotechnological applications in health care, food, and agriculture. Very few research groups worldwide are working on molecular mechanisms underlying the potential of such applications (Table 1). The present chapter highlights the applications of marine polyextremophiles.

Table 1 Polyextremophiles/extremophiles: habitats, survival and defensive strategies, and bioactive compounds and their potential applications in biotechnology
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2 Hydrolases from Marine Microorganisms

The marine polyextremophiles were investigated for the production of hydrolases. These include amylases, cellulases, peptidases, xylanases, chitinases, pullulanases, beta-xylosidase, lipases, and phytases produced by hyperthermophiles, psychrophiles, halophiles, and piezophiles. These marine extremozymes are stable and function in harsh physicochemical conditions. These are useful in food, fodder, biofuel production, medicine, and pharmaceutical and fine chemical industries (Gomes and Steiner 2004; Dalmaso et al. 2015).

3 Bioactive Compound from Marine Microorganisms

Marine microorganisms are always attractive to science. They are capable of producing unique color pigments with broad-ranging pharmacological activities. These have industrial and commercial applications. Microorganisms that produced biologically active and unique compounds include marine Bacillus, Pseudomonas, Pseudoalteromonas, Streptomyces, Vibrio, and Cytophaga isolated from seawater and sediments from sea and coastal region and bacteria associated with marine algae (Sargassum and Codium). They have produced biotechnologically important products such as alkaloids (prodiginines and tambjamines), indole derivatives (quinines and violacein), macrolides, terpenoids, polyenes, and peptides (Soliev et al. 2011; Soria-Mercado et al. 2012).

Several red, violet, yellow, and red to pink pigments were isolated from marine bacteria. Serratia marcescens have produced prodiginines (red-pigmented prodigiosin compounds) as a secondary metabolite. The polyunsaturated hydrocarbon containing 40 carbon molecules is called as carotenes. It exhibits red to pink coloration due to the presence of a wide variety of isoprenoid compounds (β-carotene, lycopene, phytofluene, and phytoene). These carotenoid or carotenoid-like compounds were produced by marine microorganisms related to the Cytophaga-Flavobacterium-Bacteroides group. Similarly, Salinibacter has contributed a lot in the production of carotenes in salterns. The marine bacterium Agrobacterium aurantiacum have carotenoid biosynthesis gene cluster, which has a role in the production of pigment astaxanthin. Paracoccus haeundaensis is another astaxanthin producer isolated from the marine environment. Like Paracoccus haeundaensis, Chromobacterium has the ability to produce the violet pigment indole derivative – violacein. The pigments (prodiginines, carotenes, violacein, phenazine compounds, quinines, glycosylated and pigmented anthracycline antibiotics (fridamycin D, himalomycin A and B), tambjamines, melanins, and other pigmented compounds) produced by marine microorganisms are biologically active compounds. On the other hand, various deep-sea fungi such as Acremonium, Alternaria, Aspergillus, Chaetomium, Cladosporium, Exophiala, Engyodontium, Fusarium, Phoma, Penicillium, Hormonema, Rhodosporidium, Rhodotorula, Schizophyllum, Tilletiopsis, Tritirachium, and Sistotrema produced polyketide compounds, steroid derivatives, indole derivatives, sesquiterpenoids, alkaloid compounds, aromatic compounds, pyrone analogues, sorbicillin derivative, breviane derivative, compounds containing amino acid structure, novel cyclopentenone, trichoderone, prenylxanthones, depsidone-based analogues, citromycetin analogue, diketopiperazine derivatives, hydroxyphenylacetic acid, and other compounds showing inhibitory activities. These are useful in health care, medicine, pharmaceuticals, and cosmetics as antibacterial, antiviral, antimalarial, antiplasmodial, antiprotozoal antibiotic, algicidal, immunosuppressant, anticancer, anti-inflammatory, antiproliferative, antioxidation, cytotoxic, and protecting agents from UV irradiation (Shieh et al. 2003; Yi et al. 2003; Matz et al. 2004; Lee et al. 2004; Zhang et al. 2005; Nakashima et al. 2005; Kim et al. 2007; Williamson et al. 2007; Feher et al. 2008; Yada et al. 2008; Becker et al. 2009; Mayer et al. 2010; Ahmad et al. 2013; Wang et al. 2015; Simon-Colin et al. 2015).

4 Exopolysaccharides from Marine Bacteria

The diversity of marine microorganisms producing exopolysaccharides (EPSs) is an unexplored area. Its detailed study may lead to the discovery of new molecules and biocatalysts useful in food products, human therapeutics, and pharmaceuticals. The marine EPS producers secrete capsular polymers in their surrounding environment. These secreted EPS polymers remain attached to the cell membrane through the lipopolysaccharides (LPSs) and give a slimy texture to the colonies of producers. This produced slimy LPS may be slowly dispersed into the environment. EPS produced by marine microorganisms combines with other bacterial polysaccharides such as alginate and chitosan which generate resistance to diseases in host. Additionally, it also increases adhesion to the surfaces, exhibits cell integrity, traps nutrients, and protects the host cells from the impact of toxic compounds and adverse freezing-like conditions (Nicolaus et al. 2010; Freitas et al. 2011; Donot et al. 2012; Mehta et al. 2014; Delbarre-ladrat et al. 2014; Finore et al. 2014).

5 Natural Bioactive Products from Marine Hydrothermal Vent Environments

Piezo-acido-hyperthermophiles and piezo-halo-psychrophiles, such as Streptomyces, Micromonospora, Rhodococcus marinononascens, Bathymodiolus septemdierum, Thermococcus S 557, Methanococcus jannaschii, Bathymodiolus septemdierum, Halomonas LOB-5, Calyptogena soyoae, Thermovibrio ammonificans, etc., are capable to produce thousands of biologically active neutral compounds. These polyextremophiles have produced microbial metabolites such as archaeal glycerol ethers, sterols, loihichelins (A–F amphiphilic peptidic siderophores), ammonificins, and amphiphilic siderophores. These produced industrially important microbial metabolites that are useful in the treatment of cancer (Fig. 1), Alzheimer’s, Parkinson’s, dementia, and other human diseases (Thornburg et al. 2015; Corinaldesi 2015).

Fig. 1
figure 1

Proposed hypothetical mechanism mediated by extremolytes in H. elongata (adapted and modified from Copeland et al. 2013)

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6 Future Perspectives

It is vital that marine extremophiles cope and withstand under extreme harsh environmental conditions. They have developed defensive mechanisms to survive in extremes, and their metabolisms play key roles in survival processes. The adaptability of extremophiles arrives from their altered genes and protein, which enables marine extremophiles to produce extremolytes having potential biotechnological applications in the treatment of cancer and degenerative diseases (Alzheimer’s, Parkinson’s, and dementia) (Calderon et al. 2004; Kanapathipillai et al. 2005; Graf et al. 2008; Kuhlmann et al. 2011; Babu et al. 2015). The produced extremolytes help them to survive and function under harsh physicochemical conditions. Currently, the research is focused on and aiming the polyextremophiles, extremonelles (cell organelles of extremophiles such as mitochondria), and extremolytes’ functions in damaging environments. The hypothetical survival mechanisms explain better to understand the survival mechanism of marine extremophiles (Fig. 1).

6.1 Use of Ectoine (5-2-Methyl-1,4,5,6-Tetra-Hydro-Pyridine-4-Carobylic Acid) in Cancer Treatment

Exposure to high level/dosage of radiation leads to alteration of DNA structure. If cellular machinery did not repair the DNA, it will produce cancer. Halophilic bacterium Halobacter elongate (H. elongate) has a mechanism of ectoine biosynthesis, which neutralizes the impact of high UV radiation exposure/dose. This has a role in cancer treatment (Fig. 1). H. elongate produce ectoine from aspartate semi-aldehyde (ASA). The immune-protective effects of ectoine which treat Langerhans cells and protect DNA from damage (i.e., from cancer) are explained using three-step processes summarized in Sect. 15.6.2 of this chapter.

6.2 Hypothetical Model for Development of Therapeutic Proteins/Products for Treatment of Neurodegenerative Diseases Using Extremophiles/Extremonelles/Extremolytes

The neurodegenerative diseases (Alzheimer’s, Parkinson’s, and dementia) are the causative for cell death. The cell death occurred due to oxidative stress (as a result, apoptosis and necrosis occur in healthy cells), which leads to the formation of deadly mitochondrial diseases (http://www.projectsmagazine.eu.com/randd_projects/mitochondrial_mechanisms_of_disease_lessons_from_extremophiles). In these types of mitochondrial diseases, the cell walls were ruptured. These lysed products of the cells will be studied for understanding mechanisms of cell death. On the other hand, investigations are in progress on extremophiles, extremonelles, and their stable extremolytes functioning under harsh environmental conditions. Further research is planned to study the ecology and physiology of extremophiles to understand the surviving properties of extremophiles. It is necessary to identify the macromolecules that make the mitochondria and other cellular organs tenacious to damages. The identification will be carried out for critical proteins and enzymes that avoid the cell death. Also, we have planned to focus and perform studies on synthesis of proteins and enzymes, bioassay, and sequencing of mRNA of protein of interest. This will allow developing of drugs that reduce the efficacy of cell death inducer proteins/enzymes/macromolecules. The developed drug will be studied for its efficacy, nontoxicity, and stability using cell lines. After successful trials on cell lines, the experiments will be planned to carry out on experimental animals.

Thus, the ectoine-mediated neutralization and developments of new drugs/macromolecules may reduce or prevent dehydration of skin and skin aging and may be used in treatments of neurodegenerative diseases such as Alzheimer’s, Parkinson’s, dementia, and Machado-Joseph disease.

Conflicts of Interests

Author(s) declares there is no conflict of interests.