Current Biotechnology - Volume 5, Issue 1, 2016

Background: Duckweed is the common name for Lemnaceae, a plant family consisting of five major genera: Lemna, Spirodela, Wolffia, Wolffiella and Landoltia. They are the world's smallest and simplest flowering plants with a high growth rate under appropriate environmental conditions. Duckweed can be used as a feed source for livestock and poultry, as well as biomass for production of biofuel and recombinant proteins. Over the last 40 years a great deal of research has been published on the use of duckweed to treat wastewater. These plants can recover nutrients, such as nitrogen and phosphorus, and they can also remove or accumulate metals, radionuclides, and other pollutants in their tissues. Methods: A summary of some of the published works done on duckweed species to remediate natural, domestic, industrial and agricultural wastewaters is presented. The potential of these species for phytoremediation is considered and discussed. Results: Certain duckweed species have the ability to grow on wastewaters, making their biomass production an environmentally friendly process. Duckweed has been extensively studied in pilot-studies and in tertiary treatment of municipal and industrial wastewaters, as well as nutrient recovery from swine wastewater. A relevant number of studies concerns the behaviour of duckweed species towards heavy metals and other elements, such as selenium and arsenic. More recently the attention has been also focused on metals, named Rare Earth Elements (REE) and on emerging pollutants (i.e. pharmaceuticals, personal care products, pesticides and surfactants). The phytoremediation ability of duckweed depends on the growth conditions of the species, the type of pollutants and their concentrations. Conclusion: Progress has been made on use of duckweed in phytoremediation. Current knowledge on the removal efficiencies of several pollutants is limited to laboratory experiments and batch systems, rarely on microcosm- or mesocosm-scale. The removal mechanisms involved, the toxicity to plants caused by contaminants, and the influences of certain important environmental parameters are not fully elucidated. Further studies in this area are still needed in order to provide more and better convincing evidence of the remediation performance of larger laboratory-scale, pilot-scale or fullscale of duckweed.

Background: When a human being is infected with a virus, antibodies are produced against many epitopes or multiple virus proteins. A subset of these antibodies can block virus infection by a process that is called neutralization. Recent research has proved that Human antibodies to human immunodeficiency virus-1 (HIV-1) can neutralize a broad range of viral isolates in vitro and protect non-human primates against infection. Methods: We review technical papers, reviews and other articles related to neutralizing monoclonal antibodies specific for HIV that are being investigated for use in HIV prevention. Results: This review will allow to gain a more general view of the mechanism of action of neutralizing antibodies, applications of neutralizing antibodies in treating various diseases and its significant role in HIV therapeutics. Conclusion: Most of the neutralizing antibodies are directed towards the Env, which the viruses keep mutating to avoid the host immune responses. Therefore, successful vaccines should induce antibodies that are capable of binding and neutralizing a broad spectrum of circulating viral products.

Background: Canopy light environment plays a crucial role in plant growth and development. Gasdischarge lamps (GDLs) are typically used in controlled-environment crop production system for illuminating crops. GDLs have broad emission spectra and heat-up significantly during operation. The advent of light-emitting diodes (LEDs) has provided the means for developing a lighting system for growing crops that is more power-economical and customizable than the conventional lighting systems. LED treatments with specific irradiation wavelengths and intensities may trigger photoreceptors to induce desired morphological and physiological changes in the crops. Objective: The present review describes the advantages of LEDs over the conventionally used GDLs from the perspective of its implementation in controlled-environment crop production along with its working principle and potential. Methods: Various food crops and ornamental plants were grown in controlled-environment chambers under LED treatments of various wavelengths. A variety of parameters including morphological, physiological and biochemical were studied to assess the impact of LEDs on plant growth and development. Results: Salient features of controlled-environment plant growth experiments conducted with LEDs as the light source have been summarized, outlining the variety of responses exhibited by different plant species to specific LED treatments. Conclusion: LED lighting systems are capable of providing customized light treatments to improve yield and enhance various qualitative traits in different crop species. The studies are thus indicative of the potential of LEDs as the next generation light source for controlled-environment crop production.

Background: Recent advances in nanotechnology and gene therapy have created new avenues for therapeutics. However, only a few studies have combined these successful systems for biomedical applications. This review presents an overview of currently available nanoparticle-vector hybrid delivery strategies, the challenges and potential solutions to their widespread use. Methods: A comprehesive analysis of literarure on the subject was carried out to identify viral vectors that have been coupled with nanomaterials. The outocome of various studies have been depicted with key aspects on their structure and functionality illustrated. Results: Gene delivery strategies using viral vectors or nanoparticles have been used extensively to deliver functional genes to many target issues. The hybrid vector systems offer immense potential in terms of their abilities to deliver more than one transgene, evade host immune response by potential masking of the immunogenic epitopes on the viral vectors and a sustained release mechanism in the target tissue. However, it is also imperative to understand that the development of such hybrid systems requires extensive knowledge of virus structure and the ability to understand the effect of nanoparticle coating on the physio-chemical properties of the vectors. Conclusion: Combination of viral and nanoparticle delivery vehicles will require an optimal ratio of nanomaterial with vector to preserve their individual characteristics and still achieve optimal tissue targeting and gene delivery. In addition, the long-term survival of such hybrid systems in the host depends on a rapid yet sustained release of their cargo and avoidance of host immune surveillance.

Background: Autotrophic Clostridia are of considerable interest for use in renewable biofuel and biocommodities production. One such autotrophic Clostridium, Clostridium ljungdahlii, was the first to be identified as an ethanologenic acetogen and has been extensively studied as a microbial catalyst for the conversion of biomass derived synthesis gas to biofuels. To better exploit this bacterium for bulk chemicals (including biofuels) production from CO2, the genome for C. ljungdahlii has been solved and genome-scale modeling performed. In this paper, the historical factors which initiated interest in the microbe, the major scientific findings obtained through the study of this organism, and its utility in the biofuels/biochemical industry are reviewed. Discussion of new areas of study for this organism and biocatalyst improvements of industrial Clostridial strains are also provided. Methods: The available literature on C. ljungdahlii including academic articles and patents have been reviewed and summarized. To better understand why C. ljungdahlii became an industrial biocatalyst for bioethanol production, the history of bioethanol as a fuel and fuel additive in the United States leading up to the bacterium’s discovery and surrounding its development was also reviewed and summarized. Results: The focus of early research on C. ljungdahlii was understanding how to optimize bioethanol production from synthesis gas. Bioethanol was of great interest as a non-petroleum fuel oxygenate and alternative fuel after the oil crisis in the 1970s, and mixing of bioethanol into transportation fuel was mandated in the 2000s. The findings of the initial research efforts with C. ljungdahlii resulted in the incorporation of the first dedicated synthesis gas-derived bioethanol production company. More recent research interest has resulted from the publication of the C. ljungdahlii genome and development of transformation methods, which has fostered research focused on understanding energy conservation at the genetic level and genetically modifying the C. ljungdahlii to produce non-native biocommodities. Despite technical challenges that have prevented commercial production of U.S. mandated quantities of bioethanol from synthesis gas, investment is still being made in developing this technology and new applications of this biocatalyst including electrosynthesis and carboxylic acid reduction are currently under investigation. Conclusion: C. ljungdahlii is an industrial biocatalyst and is a model organism of energy conservation for acetogenic bacteria. The genome sequence of C. ljungdahlii and new genetic tools that have been developed have provided researchers with the resources to fully elucidate the energy conservation processes that operate in this bacterium, determine the electrical pathway which enables C. ljungdahlii to synthesize complex chemicals using electricity, and enhance C. ljungdahlii strains for commercial production of bioethanol and biocommodities.

Background: Agricultural activities generate large amounts of biomass residues and improper management of the biomass contributes to water, soil and air pollution. The quest to manage waste agricultural biomass and convert it into bioresource is therefore of great concern. Methods: Fourteen fungal species isolated from decaying wood were identified and production of extracellular lignocellulolytic enzymes from the white and soft rot fungi grown on corn cob, coconut husk, wheat bran, rice bran and sawdust under submerged fermentation conditions was studied. Production of lignocellulolytic enzymes by Trichoderma koningii, Sporothrix carnis, Penicillium spiriulosum, Penicillium roquefortii and Penicillium restrictum were evaluated at the end of 192 hour fermentation period and the agricultural biomasses which supported highest enzyme yield were determined. Results: All lignocellulosic biomasses under study supported the production of lignocellulolytic enzymes from the fungal isolates in varying yields. Sporothrix carnis gave the highest yield of lignocellulolytic enzymes on all substrates. Corn cob supported maximum yield of lignocellulolytic enzymes from Sporothrix carnis (750 U/mg cellulase; 512 U/mg xylanase; 576 U/mg laccase and 604 U/mg peroxidase) while sawdust supported maximum yield of the enzymes from Trichoderma koningii. Coconut husk and wheat bran were found to be best substrates for laccase and peroxidase production from Penicillium species under study. Conclusion: Our findings show that agricultural biomasses are effective low cost substrates for the production of high yield of lignocellulolytic enzymes from fungi under study and the improved yield of these enzymes suggests their suitability for use in industrial applications.

Background: Thermostable alkaline lipases have commercial value and find applications in various industrial and biotechnological sectors such as additives in detergents and food industries, environmental bioremediations and in molecular biology. To use any lipase for esterification or any other application, it is important to purify and characterize the enzyme and study its properties. The aim of this paper to purify and characterize lipase from thermophilic Geobacillus sp. Methods: Lipase was purified to homogeneity by ammonium salt precipitation and column chromatography i.e. Sepharose column (size 12 × 2 cm) (Sigma Chemicals, USA) and gel filtration chromatography (size 12 × 2 cm) (Sigma Chemicals, USA). The SDS-PAGE was performed on 10% polyacrylamide gel (with 4% stacking gel) using reference molecular weight markers (Genei, Bangalore, India). The purified lipase was further characterized for various parameters. Results: The results revealed that the enzyme was purified to 5.4-fold after Sephacryl S-300 chromatography. The purified lipase showed a single band on a 10% SDS-PAGE and molecular mass of enzyme was found to be 97 kDa. The purified enzyme of Geobacillus sp. exhibited maximum lipolytic activity at temperature 55°C and pH 9.5. The half life of the lipase of Geobacillus sp. at 55°C was found to be 90 min. Conclusion: Lipase produced by Geobacillus sp. is most suitable for industrial applications because of its thermostablity, easier production, relatively inexpensive fermentation techniques and alkaline pH range, which enables its use in organic synthesis applications such as synthesis of esters, biodiesel and flavoured compounds.