Magnetic iron oxide nanoparticles are among metal nanoparticles that attract huge attention in many biotechnological fields especially in the biomedical area. Their extensive capabilities and easy separation methodology drive them to be an interesting point to many researchers. Biosynthesis is of a major importance among different methods of nanoparticles production. Microbial synthesis of these nanoparticles by bacteria and yeasts have been reported on a wide scale. However, biosynthesis using halophilic archaea is still in an early stage. This study reveals the first contribution of the haloarchaeon Halobiforma sp. N1 to the nanobiotechnology field. It reports a rapid and economical one-step method of fabricating functionalized superparamagnetic iron oxide nanoparticles and their feasibility for hyperthermia treatment for cancer therapy. Herein, we have focused on optimizing the quantity of these fascinating nanoparticles, obtaining a very high yield of 15 g l−1 with high dispersion in water solution. Their unique characteristics enable them to participate in medical applications. They are nearly spherical in shape with a high degree of homogenity and uniformity with average diameter of 25 ± 9 nm. Also, the magnetic properties and elemental structure of the formed nanoparticles tend to be superparamagnetic like behavior with saturation magnetization of 62 emu g−1 and purity of 98.38% of iron oxide, respectively. The specific absorption rate (SAR) was measured and the particles induced significant heating power at lower frequencies which is a promising result to be applied for in vitro/in vivo hyperthermia studies in the near future.

Bacterial nanocellulose (BNC) is a nanofibrillar polymer that possesses unique characteristics such as high chemical purity, mechanical strength, flexibility, and absorbency. In addition, different bacterial strains can form nanocellulose (NC) in multiple shapes and sizes. This study describes the first report of a marine Bacillus strain that is able to synthesize NC. The strain identified as B. velezensis SMR based on 16S rDNA sequencing, produced highly structured NC, as confirmed by X-ray diffraction (XRD) and Scanning Electron Microscopic Analysis (SEM). In Hestrin-Schramm (HS) medium, B. velezensis SMR produced twice the quantity of BNC in comparison to the reference strain, G. xylinus ATCC 10245. The ability of B. velezensis SMR to produce NC using different industrial waste materials as growth media was tested. Growth in Ulva seaweed extract supported a 2.5-fold increase of NC production by B. velezensis SMR and a threefold increase in nc production by G. xylinus ATCC 10245. As proof of principle for the usability of nc from B. velezensis SMR, we successfully fabricated a BNCbased polyvinyl alcohol hydrogel (BNC-PVA) system, a promising material used in different fields of application such as medicine, food, and agriculture. Bacterial nanocellulose (BNC), an extracellular produced structure, is considered a highly desirable biomaterial due to its superior qualities in comparison to other cellulose-containing structures. Compared to plant cellulose, nanofibril network of biocellulose possesses high water retaining capacity, degree of polymerization, chemical purity, high crystallinity, in vivo biocompatibility to be used as a scaffold in tissue engineering, and excellent mechanical properties 1,2. BNC production has been reported in both Gram-negative bacteria such as G. xylinus, Agrobacterium, Achromobacter, Aerobacter, Azotobacter, Pseudomonas, and Rhizobium, and Gram-positive bacteria such as Sarcina 3. Among the different BNC-producing bacteria, G. xylinus is the most commonly studied species 4. Synthesis of BNC is a complex process involving polymerization of glucose monomers and secretion of the complex cellulose structures to the external environment to create a three-dimensional microfibril and nanofibril network. During the fermentation process, bacteria either move freely in the media or attach to cellulose fibers, producing a highly swollen gel structure 5. Purification of NC from the culture medium involves the removal of bacterial cells and collection of the cellulose matrix from the cultural medium. This is a crucial step to ensure the quality of BNC and can be performed either by repeated washing using a hot sodium hydroxide solution, followed by water until reaching a neutral pH or by other methods, such as gamma radiation 6. While BNC-production by several bacterial species have been reported, it has never been shown that members of the genus Bacillus were able to produce NC. B. velezensis is a Gram-positive bacterium that has been extensively studied for its ability to induce plant growth-...

Biofilm forming bacteria are omnipresent in the marine environment. Pseudoalteromonas is one of the largest within the γ-proteobacteria class, and a member of marine bacteria. Species of Pseudoalteromonas are generally found in association with marine eukaryotes. In this work, we present the isolation and characterization of two strains forming biofilm on rock surface and associated with marine sponge. They were identified using 16SrDNA as Pseudoalteromonas prydzensis alex, and Pseudoalteromonas sp. alex. They showed the highest titer in biofilm formation quantified using the test tube method using crystal violet.

Surfaces submerged in seawater are colonized by various microorganisms, resulting in the formation of heterogenic marine biofilms. This work aims to evaluate the biofilm formation by Cobetia marina alex and doing a comparative study between this promising strain with the two bacterial strains isolated previously from the Mediterranean seawater, Alexandria, Egypt. Three strains; Cobetia marina alex, Pseudoalteromonas sp. alex, and Pseudoalteromonas prydzensis alex were screened for biofilm formation using the crystal violet (CV) quantification method in a single culture. The values of biofilm formed were OD600= 3.0, 2.7, and 2.6, respectively leading to their selection for further evaluation. However, factors affecting biofilm formation by C. marina alex were investigated. Biofilm formation was evaluated in single and multispecies consortia. Synergistic and antagonistic interactions proved in this work lead to the belief that these bacteria have the capability to produce some interesting signal molecules N-acyl Homoserine Lactones (AHLs)

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