Toward biomanufacturing of next-generation bacterial nanocellulose (BNC)-based materials with tailored properties: A review on genetic engineering approaches.

Bacterial nanocellulose (BNC) is a biopolymer that is drawing significant attention for a wide range of applications thanks to its unique structure and excellent properties, such as high purity, mechanical strength, high water holding capacity and biocompatibility. Nevertheless, the biomanufacturing of BNC is hindered due to its low yield, the instability of microbial strains and cost limitations that prevent it from being mass-produced on a large scale. Various approaches have been developed to address these problems by genetically modifying strains and to produce BNC-based biomaterials with added value.

Citrate-buffered Yamanaka medium allows to produce high-yield bacterial nanocellulose in static culture using strains isolated from apple cider vinegar.

Bacterial nanocellulose (BNC) is a sustainable, renewable, and eco-friendly nanomaterial, which has gained great attentions in both academic and industrial fields. Two bacterial nanocellulose-producing strains (CVV and CVN) were isolated from apple vinegar sources, presenting high 16S rRNA gene sequence similarities (96%-98%) with species. The biofilm was characterized by scanning electron microscopy (SEM), revealing the presence of rod-shaped bacteria intricately embedded in the polymeric matrix composed of nanofibers of bacterial nanocellulose.

Hybrid nanomaterial composed of chitosan, curcumin, ZnO and TiO for antibacterial therapies.

Metal nanoparticles have been tremendously utilised, such as; antibacterial and anticancer agents. Although metal nanoparticles exhibits antibacterial and anticancer activity, but the drawback of toxicity on normal cells limits their clinical applications. Therefore, improving the bioactivity of hybrid nanomaterial (HNM) and minimizing toxicity is of paramount importance for biomedical applications.

An ecofriendly nanocomposite of bacterial cellulose and hydroxyapatite efficiently removes lead from water.

An environmentally friendly nanocomposite adsorbent composed of two renewable biomaterials, bacterial cellulose (BC) nanofibrils and hydroxyapatite (HA) nanocrystals, was synthetized by an in situ wet chemical precipitation technique, using clam shell biowaste as feedstock. HA nanocrystals embedded in an ultrafine BC network were confirmed and characterized trough different instrumental techniques (SEM, FTIR, XRD, EDS, surface charge and BET analysis), describing its nanostructure, chemical composition and thermal stability. The adsorptive removal of lead ions by the nanocomposite was investigated through batch experiments conducted under different pH, contact times and Pb(II) initial concentrations, proving that the process was highly favorable according to the Langmuir isotherm model (monolayer adsorption) with chemisorption as the main mechanism and kinetic data obeying a nonlinear pseudo-second order kinetic model.

Marine plastic debris in Central Chile: Characterization and abundance of macroplastics and burden of persistent organic pollutants (POPs).

In this study, we characterized plastic debris (PD) found on beaches from Concepción Bay in central Chile during spring 2017 and summer 2018. The identification of polymers was carried out using FT-IR. Persistent organic pollutants (POPs) were extracted with hexane using an ultrasonic bath and further quantified through GC-MS.

Persistent organic pollutants sorbed in plastic resin pellet - "Nurdles" from coastal areas of Central Chile.

Plastic resin pellets were collected from coastal areas (n = 7) of central Chile. Pellets were analyzed using Fourier-transform infrared spectroscopy for polymer identification and gas chromatography-mass spectrometry for Persistent Organic Pollutants (POPs) determination. Screened compounds were PBDEs (n = 10), PCBs (n = 7), and OCPs (n = 13).

Heavy metal removal from aqueous systems using hydroxyapatite nanocrystals derived from clam shells.

Hydroxyapatite (HA) was synthesized by wet chemical precipitation, using clam shell (CS) waste as feedstock. SEM and TEM observation of the produced hydroxyapatite revealed the presence of rod-shaped nanocrystals, while XRD and EDS analyses confirmed the characteristic patterns of hydroxyapatite molecules. This material was subsequently employed as a sorbent for heavy metal removal from aqueous solutions, both in batch and column equilibrium procedures.

Generation of engineered core-shell antibiotic nanoparticles.

Well-defined nanocomposite structures have received significant attention due to their superior combinatorial properties. Rational tuning of the core and shell of the nanostructure(s) can offer potent antibacterial activity. Such advanced core-shell nanocomposite methodologies allow not only the incorporation of antibacterial agents on the shell but also provide its stability and nurture antibacterial activity.

Presence and characterization of microplastics in fish of commercial importance from the Biobío region in central Chile.

In this study we have identified and characterized microplastic particles (MPs) found in six fish species of commercial importance in central Chile. The fish species belong to different trophic levels and were obtained from the oceanic and coastal habitats. To analyze MPs, the fish gastrointestinal content was extracted, analyzed and characterized using a microscopy equipped with Fourier-transform infrared spectroscopy (FT-IR).

Trickling filter technology for biotreatment of nitrogenous compounds emitted in exhaust gases from fishmeal plants.

Odour emissions are a major environmental issue associated with fishmeal production. Laboratory-scale biotrickling filters (BTFs) were inoculated with microbial consortia derived from sewage sludge, with the goal to study the biotreatment of low-loads of methylamines and ammonia that are main components of odorous exhaust gases produced by fishmeal processing plants. A BTF packed with ceramic rings was subjected to a real fishmeal plant emission containing trimethylamine (TMA), dimethylamine (DMA) and monomethylamine (MMA).

Nano-hydroxyapatite polymeric hydrogels for dye removal.

Herein, two kinds of nano-hydroxyapatite were synthesized from Clam and Magellan shell by wet chemical precipitation method. Mainly, carboxymethyl cellulose/acrylamide/nano-hydroxyapatite composite hydrogels were developed a free-radical polymerization process and investigated as a sorbent for Acid Blue 113 (AB) from aqueous AB solution. The swelled and kinetic behaviours of hydrogels were investigated using a gravimetric method.