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Downstream Processing of Waste Biomass: From Biophysical Aspects of Biomass Yield to Engineered Microbial Cells for Better Harvesting
Published in Prakash K. Sarangi, Latika Bhatia, Biotechnology for Waste Biomass Utilization, 2023
However, if we look at it, the phenotypic trait modulation, initially it was in agriculture and biomedical applications. For example (Peters et al., 1981), the genetic engineering of symbiotic N2-fixation and conservation of fixed nitrogen. Several examples for poultry and veterinary feed-related application are also available. Recombinant DNA technologies now allow for the economic production of a variety of feed supplements as well such as microbial phytases. Similarly, applications in other industries also can be mentioned. Increased production of zeaxanthin and other pigments (Lagarde et al., 2000) by application of genetic engineering techniques in Synechocystis sp. is also there. As early as 1997, the genetic engineering of resistant traits to bleaching herbicides affecting phytoene desaturase and lycopene cyclase in cyanobacterial carotenogenesis was reported (Windhoevel et al., 1997).
Fucoxanthin
Published in M. Jerold, V. Sivasubramanian, Biochemical and Environmental Bioprocessing, 2019
Lohr and Wilhelm (1999) found out that violaxanthin as the major precursor for the synthesis of almost all carotenoids. Fucoxanthin in the diatom Phaeodactylum tricornutum was synthesized from violaxanthin through diadinoxanthin. Lichtenthaler (1999) proved that isopentenyl pyrophosphate (IPP) was synthesized in 1-deoxy-D-xylulose-5-phosphate (DOXP) pathway from pyruvate and glyceraldehyde. Phytoene synthase converts IPP to phytoene, a C40 compound. Oxygenic phototrops require three enzymes for the conversion of phytoene to lycopene. They are phytoene desaturase, δ-carotene desaturase, and cis-carotene isomerase. Bacteria use only phytoene desaturase for the conversion of phytoene to lycopene. Then lycopene is converted to β-carotene by lycopene cyclase (Wang et al., 2014). β-Carotene is hydroxylated by β-carotene hydroxylase to zeaxanthin (Takaichi, 2011).
Biofuel and Biochemical Production by Photosynthetic Organisms
Published in Kazuyuki Shimizu, Metabolic Regulation and Metabolic Engineering for Biofuel and Biochemical Production, 2017
Another important aspect of utilizing photosynthetic organisms is their ability of producing pharmaceuticals due to the reduction of ketones (Havel and Weuster-Botz 2007, Nakamura et al. 2000, Yang et al. 2012). Microalgae are attractive for their production of antioxidants, where Fischerella ambigua and Chlorella vulgaris show higher antioxidant activities (Hajimahmoodi et al. 2010). Phenolic compounds have antioxidant properties, where their production can be enhanced in Spirulina platensis by manipulating light intensities (Kepekci and Saygideger 2012). Phycocyanin is also attractive, where its production by Arthospira (Spirulina) platensis was investigated in marine environment (Leema et al. 2010). Lycopene is important food additives and pigment, and can be produced by a purple non-sulfur bacterium, Rhodospirillum rubrum, by deletion of downstream phytoene desaturase gene crtC and crtD (Wang et al. 2012). Moreover, PHB can be produced up to 10.6% of algal dry weight by introducing bacterial PHB forming pathway genes of R. eutropha H16 into the diatom Phaeodactylum tricomutum (Hempel et al. 2011).
Acute toxicity of three herbicide formulations of Astyanax altiparanae (Characiformes, Characidae), an emerging neotropical fish model species
Published in Journal of Toxicology and Environmental Health, Part A, 2023
Nathalia R. A. Rocha, Thiago A. Freato, José T. Filho, Admilson C. Barbosa, Talita M. Lázaro, Gabriel M. Schade, Gabriella B. Carvalho, Carlos A. F. Oliveira, José A. Senhorini, George S. Yasui, Paulo S. Monzani
Only Sonar AQ NA (fluridone) is authorized (IBAMA n° 2910/2000) for aquatic vegetation management in Brazil. Fluridone is inefficient to enhance various macrophyte growth attributed to genetic variability in aquatic plants due to differences in phytoene desaturase gene, the enzyme involved in carotenoid biosynthesis (Benoit and Les 2013). Therefore, population genetic studies of within- and among-population genetic variability are essential to managing submerged aquatic plant species (Thum et al. 2020). Other herbicides were also used experimentally to determine their efficacy in controlling aquatic vegetation, including Reglone® (Esteves et al. 2020; Pitelli et al. 2011), Arsenal® NA and other imazapyr formulations (Carvalho et al. 2005; Dugdale et al. 2020), and Roundup Transorb® and Roundup Original® (Maria et al. 2020; Souza et al. 2020).
Toxicity of herbicides to cyanobacteria and phytoplankton species of the San Francisco Estuary and Sacramento-San Joaquin River Delta, California, USA
Published in Journal of Environmental Science and Health, Part A, 2020
Chelsea H. Lam, Tomofumi Kurobe, Peggy W. Lehman, Mine Berg, Bruce G. Hammock, Marie E. Stillway, Pramod K. Pandey, Swee J. Teh
There are many mechanisms by which phytoplankton and cyanobacteria taxa could be resistant to the effects of herbicides. Resistant taxa could take up less chemical, sequester the chemical into vacuoles or cell compartments where the chemical does not exert toxic effects, degrade the chemical to nontoxic metabolites, have resistant enzymes, or employ other modifications to confer resistance. For instance, Chlamydomonas reinhardtii was found to tolerate extremely high concentrations of the broadleaf herbicide fluroxypyr (up to 0.5 mg L−1) by accumulation and rapid biodegradation of the herbicide.[64] Because of their ability to use these mechanisms, it is not surprising to see variation in resistance to herbicides between plankton species. Even within the same genus, species responses can differ greatly. For instance, one study found that the growth of the cyanobacterium Oscillatoria agardhii was inhibited by 40 µg L−1 of fluridone, while another study found the growth of O. chalybea, was not affected by fluridone up to 3293 µg L−1.[59,60] Fluridone resistance due to mutations in the phytoene desaturase enzyme are reported in hydrilla plants.[65,66] Therefore, the three species tested for this study almost certainly do not represent the full range of responses to herbicides within the cyanobacteria, diatom, and green algae taxa.