Nanotechnology is an area that has been growing over the years, being possible nowadays to find numerous materials constructed at nanoscale In addition, many applications have been attributed to these “new” materials In this review is presented a brief overview of nanoparticles used for the immobilization of enzymes Considering the extensive universe of immobilization in nanoparticles, some were chosen to be exposed here, such as chitosan, graphene, silica, polymers, magnetic, nanoflowers, among others Advantages, disadvantages and limitations of nanoimmobilization also be discussed Some applications of nanoimmobilized enzymes are presented, like as biodiesel, flavor synthesis ester and biosensors The purpose of this paper is to provide an overview of what is being studied in relation to nanoparticles for enzymes immobilization, and some discussions about them, aimed at assisting researchers in future studies and reviews

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Nanomaterials for biocatalyst immobilization – state of the art and future trends

Microalgae has been identified as a potential feedstock for biodiesel production since its cultivation requires less cropland compared to conventional oil crops and the high growth rate of microalgae. Research on microalgae oils often are focused on microalgae oil extraction and biomass harvesting techniques. However, energy intensive and costly lipid extraction methods are the major obstacles hampering microalgae biodiesel commercialisation. Direct biodiesel synthesis avoids such problems as it combines lipid extraction techniques and transesterification into a single step. In this review, the potential of direct biodiesel synthesis from microalgae biomass was comprehensively analysed. The various species of microalgae commonly used as biodiesel feedstock was critically assessed, particularly on high lipid content species. The production of microalgae biodiesel via direct conversion from biomass was systematically discussed, covering major enhancements such as heterogeneous catalysts, the use of ultrasonic and microwave- techniques and supercritical alcohols that focus on the overall improvement of biodiesel production. In addition, this review illustrates the cultivation conditions for biomass growth and lipid productivity improvement, the available harvesting and lipid extraction technologies, as well as the key challenges and future prospect of microalgae biodiesel production. This review serves as a basis for future research on direct biodiesel synthesis from modified microalgae biomass to improve profitability of microalgae biodiesel.

Sustainability of direct biodiesel synthesis from microalgae biomass: a critical review.

Bioflocculation: An alternative strategy for harvesting of microalgae - An overview.

Biofabrication and characterization of silver nanoparticles using aqueous extract of seaweed Enteromorpha compressa and its biomedical properties.

Extracellular polymeric substances (EPS) produced by microorganisms represent biological macromolecules with unfathomable potentials and they are required to be explored further for their potential application as a bioflocculant in various wastewater sludge treatment. Although several studies already exist on biosynthetic pathways of different classical biopolymers like alginate and xanthan, no dedicated studies are available for EPS in sludge. This review highlights the EPS composition, functionality, and biodegradability for its potential use as a carbon source for production of other metabolites. Furthermore, the effect of various extraction methods (physical and chemical) on compositional, structural, physical and functional properties of microbial EPS has been addressed. The vital knowledge of the effect of extraction method on various important attributes of EPS can help to choose the suitable extraction method depending upon the intended use of EPS. The possible use of different molecular biological techniques for enhanced production of desired EPS was summarized.

/pdf/critical-review-of-eps-production-synthesis-and-composition-1r8pnk1gue.pdf

Critical review of EPS production, synthesis and composition for sludge flocculation

Biosynthesis of silver nanoparticle and its application in cell wall disruption to release carbohydrate and lipid from C. vulgaris for biofuel production.

Response surface methodology assisted biodiesel production from waste cooking oil using encapsulated mixed enzyme.

Exopolysaccharides (EPSs) play an extensive role as biopolymers in the environment by replacing synthetic polymers as they are degradable, nontoxic, and produced by microorganisms. An attempt was made to optimize a medium, by the one-factor-at-a-time method, for an enhanced production of EPS from a soil isolate, Bacillus subtilis. The study was carried out by experimenting on various nutrients at different concentrations. EPS was precipitated using ethanol, the total carbohydrate content was determined by phenol sulfuric acid method, and functional groups were detected by Fourier transform infrared (FTIR) spectrophotometry. The finalized medium contained sucrose (20 g/L), yeast extract (5 g/L), NaCl (7 g/L), CaCl 2 (0.5 g/L), L-asparagine (0.05 g/L), and ascorbic acid (0.05 g/L). The carbon source was replaced with certain agro substrates, cane molasses, and rice bran. Cane molasses at a concentration of 2% gave the highest yield of 4.86 g EPS/L as compared to a medium with sucrose (2.98 g EPS/L). The effect of UV radiations on growth and synthesis was negative, decreasing the growth rate and quantity of EPS produced. Different solvents were checked for their efficiency on precipitating EPS; those other than ethanol, diethyl ether, and methanol were not able to sediment the polymer. FTIR analysis of the extracted product revealed that the polymer was made up of units of sucrose. Thus, the present study showed that the agro wastes could be an alternative for synthetic substrates, providing a way for an economical production of EPS.

https://journals.tubitak.gov.tr/biology/issues/biy-13-37-3/biy-37-3-5-1206-50.pdf

Medium optimization for the production of exopolysaccharide by Bacillus subtilis using synthetic sources and agro wastes

The present study aimed at directly producing biodiesel using oil extracted from wet cells of marine microalga, Chlorella salina . The protocol involved cellulase for oil extraction and lipase for oil conversion to FAME during interesterification immobilised on magnetic nanoparticles. Anaerobically synthesized magnetic nanoparticles were characterized using TEM and XRD Spectroscopy. Studies were also carried out to learn the effect of immobilised enzymes on their respective operations and water content for FAME synthesis. The investigation showed that 2 g of each immobilised enzyme- cellulase and lipase was found to be optimum for oil extraction and FAME conversion respectively and 60% water was required for biodiesel production. A maximum yield was observed as 93.56% under optimised conditions along with standard parameters. Experiment on stability and re-utilization of immobilised materials revealed that they remained intact without any loss in their functions even after 10 cycles of repeated usage. The overall study represented that it is a rapid and economical prospect for producing biodiesel commercially in a greener way causing negligible harm to ecosystem.

Sirajunnisa Abdul Razack

Papers

Biosynthesis of silver nanoparticle and its application in cell wall disruption to release carbohydrate and lipid from C. vulgaris for biofuel production.

Response surface methodology assisted biodiesel production from waste cooking oil using encapsulated mixed enzyme.

Medium optimization for the production of exopolysaccharide by Bacillus subtilis using synthetic sources and agro wastes

Direct conversion of lipids from marine microalga C. salina to biodiesel with immobilised enzymes using magnetic nanoparticle

Statistical optimization of harvesting Chlorella vulgaris using a novel bio-source, Strychnos potatorum.