Sucrose Production Research Articles

Beta maritima. The origin of beets

The book is dedicated to Beta maritima, a single species of the genus Beta and progenitor of various cultivated relatives known as sugar beet, garden beet, mangold, fodder beet and energy beets. Importantly, B. maritima is closely related to sugar beet, the only crop for sucrose production under temparate climate conditions and a crop with high potential for sustainable energy. The book is divided into eight chapters with multiple subheadings, each highlighting different aspects of B. maritima. In general, the book is well illustrated with many figures printed in colour. The first chapter describes the history of B. maritima and its domestication. Early uses as a wild vegetable, herb or medical plant were followed by cultivation, which most likely began in Asia Minor, one of the natural habitats of the species. This chapter is very nicely illustrated and interesting as it gives a comprehensive overview of many ancient bibliogaphic sources with references to beet. However, the final part of this chapter describing the life and merits of scientists working on sea and cultivated beet is rather lengthy. The second chapter, entitled ‘Range of Distribution’ is short and focusses on the native distribution of B. maritima along seashores. The species is very tolerant and has a large environmental adaptibility to conditions such as high salinity and poor soil, which is related to its extreme genotypic and phenotypic variation. Beta maritima crosses efficiently with sugar beet and produces viable seeds. Contamination of sugar beet seed lots in combination with trading and shipping is considered to be the main route for the widespread occurrence of B. maritima outside European or Mediterranian coastal areas. The subject of the chapter ‘Morphology, Physiology and Ecology’ is, as its name suggests, rather broad. It gives detailed descriptions of the life cycle of sea beet from germination, organ growth and development, to flowering. This chapter gives an interesting account of pollen morphology and dispersal, and gene flow. Gene flow is generally low between sea beets and crops in areas of sugar beet seed production, but can reduce the allelic diversity of sea beets. Other topics in this chapter include reproduction systems, male sterility, interspecific crosses and survival strategies. The taxonomy is an important issue and subject of the forth chapter, and the authors give a comprehensive overview about the numerous attempts to classify Beta species, which had already started in the late 17th century. The current status of the taxonomy of the genus Beta is still not satisfactory, even after splitting of the Procumbentes section from the genus. Hence this chapter is a valuable contribution, although a conclusive taxonomy of the genus is missing and still a matter of future research, as the authors correctly state. After a short consideration of the historical and potential use of sea beets in Chapter 5, Chapter 6 is a major and important part of the book. Beta maritima is extremely important for sugar beet breeding and serves as the main reservoir and source for resistance genes. The species is resistant against many pathogenes, in particular viruses and fungi, but also to nematodes and insects. Moreover, B. maritima is highly tolerant to drought, heat and, as mentioned above, salanity. Most importantly, sea beets can easily be crossed with sugar beet, thus providing a route for the transfer of genes for desirable agronomic traits into cultivated beet. The domestication of the sea beet as a vegetable initiated the selection of highly variable cultivars with enlarged root hypocotyles, which are nicely described and illustrated in Chapter 7. This chapter is entitled ‘Cultivated Offspring’ and covers chards, garden beet, sugar beet, fodder beets and energy beets. The latter are used for the fermentation of bioethanol, and controversial aspects of increasing either yield or sugar content are dicussed. Less importantly, but for completeness, this chapter also contains a short paragraph about ornamental beet. However, the main focus is on sugar beet and breeding aims as major crop of the genus Beta. Beta maritima introgressions are the main ressource to broaden the narrow gene pool of sugar beet. This topic is addressed in Chapter 8, where the importance of germplam conservation, collection and genebank management is described. The species of the genus Beta, in particular sugar beet, have been targets of genome analysis projects, such as marker development for genetic linkage maps, resistance gene cloning, genome sequencing and evoluionary studies of repetitive DNA sequences. It is a shortcoming of this book that most of these papers (published in international peer-reviewed journals) are not mentioned or cited. Beta maritima: the origin of beets is, in my opinion, not a textbook for students or undergraduates but it is a valuable resource for scientists involved in Beta germplasm conservation and taxonomy, as well as breeders interested in sea beet and beet history in general.

Novel Process for the Extraction of Ethyl Levulinate by Toluene with Less Humins from the Ethanolysis Products of Carbohydrates

A series of organic solvents were screened for the extraction of ethyl levulinate (EL) from the concentrated ethanolysis products of sucrose. Among these organic solvents, toluene was confirmed as an outstanding extracting agent for separating EL with less humins from the concentrated reaction products. The EL extraction rate was strongly related to the temperature and duration applied in the vacuum concentration; a maximum EL recovery of 96.7% can be achieved through the extraction by toluene from the ethanolysis products. Herein, the catalytic transfer hydrogenation (CTH) of biomass-derived EL to γ-valerolactone (GVL) was also performed over inexpensive metal oxides using ethanol as a hydrogen donor. On the basis of these scenarios, a novel process for the production and separation of EL and GVL from carbohydrates was proposed to integrate the ethanolysis of carbohydrates and the CTH of EL.

Bioavailability and stability of intravenous iron sucrose originator versus generic iron sucrose AZAD

Context: Severe iron deficiency requires intravenous iron supplementation to replenish iron stores. Intravenous iron sucrose has been used for decades for the treatment of anemia. New generic iron sucrose products are now marketed for the use in several countries and there is an ongoing discussion about the safety and efficacy of iron sucrose similars.Objective: In this study, we compared the iron sucrose originator Venofer® and the generic iron sucrose AZAD (ISA) regarding bioavailability, toxicity and stability in human THP-1 cells and HepG2 cells.Methods: The bioavailability of Venofer® and ISA was investigated in both cell types by a ferrozin-based assay. The release of incorporated iron was assayed by atomic absorption spectroscopy. Ferritin content was measured by enzyme-linked immunosorbent assay (ELISA). HepG2 cells were used to investigate the intracellular labile iron pool (LIP), which was measured by the fluorescent calcein assay. The amount of redox-active iron within the iron formulations was assayed using fluorescent dichlorofluorescein.Results: We found no significant differences in all parameters between Venofer® and ISA in regard of bioavailability, toxicity and stability in vitro.Discussion: ISA shows identical physico-chemical features and identical bioavailability in vitro. This study is a profound basis for future clinical tests with generic iron sucrose compounds.

Improved molecular tools for sugar cane biotechnology

Sugar cane is a major source of food and fuel worldwide. Biotechnology has the potential to improve economically-important traits in sugar cane as well as diversify sugar cane beyond traditional applications such as sucrose production. High levels of transgene expression are key to the success of improving crops through biotechnology. Here we describe new molecular tools that both expand and improve gene expression capabilities in sugar cane. We have identified promoters that can be used to drive high levels of gene expression in the leaf and stem of transgenic sugar cane. One of these promoters, derived from the Cestrum yellow leaf curling virus, drives levels of constitutive transgene expression that are significantly higher than those achieved by the historical benchmark maize polyubiquitin-1 (Zm-Ubi1) promoter. A second promoter, the maize phosphonenolpyruvate carboxylate promoter, was found to be a strong, leaf-preferred promoter that enables levels of expression comparable to Zm-Ubi1 in this organ. Transgene expression was increased approximately 50-fold by gene modification, which included optimising the codon usage of the coding sequence to better suit sugar cane. We also describe a novel dual transcriptional enhancer that increased gene expression from different promoters, boosting expression from Zm-Ubi1 over eightfold. These molecular tools will be extremely valuable for the improvement of sugar cane through biotechnology.

Chemical inhibition of acetyl coenzyme A carboxylase as a strategy to increase polyhydroxybutyrate yields in transgenic sugarcane

Polyhydroxybutyrate (PHB) is a naturally occurring bacterial polymer that can be used as a biodegradable replacement for some petrochemical-derived plastics. Polyhydroxybutyrate is produced commercially by fermentation, but to reduce production costs, efforts are underway to produce it in engineered plants, including sugarcane. However, PHB levels in this high-biomass crop are not yet commercially viable. Chemical ripening with herbicides is a strategy used to enhance sucrose production in sugarcane and was investigated here as a tool to increase PHB production. Class A herbicides inhibit ACCase activity and thus reduce fatty acid biosynthesis, with which PHB production competes directly for substrate. Treatment of PHB-producing transgenic sugarcane plants with 100 μM of the class A herbicide fluazifop resulted in a fourfold increase in PHB content in the leaves, which peaked ten days post-treatment. The minimum effective concentration of herbicide required to maximize PHB production was 30 μM for fluazifop and 70 μM for butroxydim when applied to saturation. Application of a range of class A herbicides from the DIM and FOP groups consistently resulted in increased PHB yields, particularly in immature leaf tissue. Butroxydim or fluazifop treatment of mature transgenic sugarcane grown under glasshouse conditions increased the total leaf biomass yield of PHB by 50%-60%. Application of an ACCase inhibitor in the form of a class A herbicide to mature sugarcane plants prior to harvest is a promising strategy for improving overall PHB yield. Further testing is required on field-grown transgenic sugarcane to more precisely determine the effectiveness of this strategy.

Iron sucrose nanoparticles: Effects on tissue iron levels and hepatic gene expression in the rat

www.citoxlab.com IntroductIon In the present study we have examined iron biodistribution and hepatic gene expression following administration of two iron sucrose preparations to rats; Iron Sucrose Azad (ISA), a generic iron sucrose product and Venofer®, a reference iron sucrose product. The biodistribution study was undertaken to address the requirement of the recent European Medicines Agency (EMA) Reflection Paper (1) that comparative data from non clinical studies on the kinetics of iron biodistribution in major target organs should be presented in support of claims of essential similarity for injectable iron sucrose preparations. We have also evaluated the potential hepatic toxicity of these preparations using a gene expression approach.

Structural basis of kinetic variations in Sucrose Phosphate Phosphatase (SPP) of rice and Anabaena unveiled through computational analysis

Sucrose is an important storage form of assimilated carbon in many plant species. Unlike other sucrose biosynthetic enzymes, Sucrose Phosphate Phosphatase (SPP), the terminal enzyme in sucrose biosynthetic pathway, is the least understood. SPPs from different organisms have different kinetic properties. The current study focuses on the structural differences among SPP homologues and unveils the probable structural basis of kinetic variations. We have employed computational methods of molecular modeling and structure comparisons and identified structural variations in some of the substrate binding residues, amino acid substitutions in regions that are lining the active site and minute structural differences that can enhance the nucleophilicity of a catalytic nucleophile (Asp 9 ). We report a structurally and hence functionally important amino acid substitution (Asp 159 by Alanine) in one of the rice SPP isoforms, which can result in the disruption of a H-bond that helps in binding of sucrose at the active site of the enzyme. In this paper we discuss the structural basis of enhanced catalytic efficiency of rice SPP in comparison with a cyanobacterium (Anabaena variabilis). The natural mutations identified in our analysis of the SPP catalytic domain would be useful in re-designing the enzyme for enhanced catalytic efficiency and higher sucrose production.

Hexokinase mediates stomatal closure

Stomata, composed of two guard cells, are the gates whose controlled movement allows the plant to balance the demand for CO2 for photosynthesis with the loss of water through transpiration. Increased guard-cell osmolarity leads to the opening of the stomata and decreased osmolarity causes the stomata to close. The role of sugars in the regulation of stomata is not yet clear. In this study, we examined the role of hexokinase (HXK), a sugar-phosphorylating enzyme involved in sugar-sensing, in guard cells and its effect on stomatal aperture. We show here that increased expression of HXK in guard cells accelerates stomatal closure. We further show that this closure is induced by sugar and is mediated by abscisic acid. These findings support the existence of a feedback-inhibition mechanism that is mediated by a product of photosynthesis, namely sucrose. When the rate of sucrose production exceeds the rate at which sucrose is loaded into the phloem, the surplus sucrose is carried toward the stomata by the transpiration stream and stimulates stomatal closure via HXK, thereby preventing the loss of precious water.

Abscisic acid induced changes in production of primary and secondary metabolites, photosynthetic capacity, antioxidant capability, antioxidant enzymes and lipoxygenase inhibitory activity of Orthosiphon stamineus Benth.

An experiment was conducted to investigate and distinguish the relationships in the production of total phenolics, total flavonoids, soluble sugars, H2O2, O2−, phenylalanine ammonia lyase (PAL) activity, leaf gas exchange, antioxidant activity, antioxidant enzyme activity [ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD) and Lipoxygenase inhibitory activity (LOX)] under four levels of foliar abscisic acid (ABA) application (0, 2, 4, 6 µM) for 15 weeks in Orthosiphon stamineus Benth. It was found that the production of plant secondary metabolites, soluble sugars, antioxidant activity, PAL activity and LOX inhibitory activity was influenced by foliar application of ABA. As the concentration of ABA was increased from 0 to 6 µM the production of total phenolics, flavonoids, sucrose, H2O2, O2−, PAL activity and LOX inhibitory activity was enhanced. It was also observed that the antioxidant capabilities (DPPH and ORAC) were increased. This was followed by increases in production of antioxidant enzymes APX, CAT and SOD. Under high application rates of ABA the net photosynthesis and stomatal conductance was found to be reduced. The production of primary and secondary metabolites displayed a significant positive relationship with H2O2 (total phenolics, r2 = 0.877; total flavonoids, r2 = 0.812; p ≤ 0.05) and O2− (total phenolics, r2 = 0.778; total flavonoids, r2 = 0.912; p ≤ 0.05). This indicated that increased oxidative stress at high application rates of ABA, improved the production of phytochemicals.

Exploring the photosynthetic production capacity of sucrose by cyanobacteria

Because cyanobacteria are photosynthetic, fast-growing microorganisms that can accumulate sucrose under salt stress, they have a potential application as a sugar source for the biomass-derived production of renewable fuels and chemicals. In the present study, the production of sucrose by the cyanobacteria Synechocystis sp. PCC6803, Synechococcus elongatus PCC7942, and Anabaena sp. PCC7120 was examined. The three species displayed different growth curves and intracellular sucrose accumulation rates in response to NaCl. Synechocystis sp. PCC6803 was used to examine the impact of modifying the metabolic pathway on the levels of sucrose production. The co-overexpression of sps (slr0045), spp (slr0953), and ugp (slr0207) lead to a 2-fold increase in intracellular sucrose accumulation, whereas knockout of ggpS (sll1566) resulted in a 1.5-fold increase in the production of this sugar. When combined, these genetic modifications resulted in a fourfold increase in intracellular sucrose accumulation. To explore methods for optimizing the transport of the intracellular sucrose to the growth medium, the acid-wash technique and the CscB (sucrose permease)-dependent export method were evaluated using Synechocystis sp. PCC6803. Whereas the acid-wash technique proved to be effective, the CscB-dependent export method was not effective. Taken together, these results suggest that using genetic engineering, photosynthetic cyanobacteria can be optimized for efficient sucrose production.

Levans production by Gluconacetobacter diazotrophicus

Fil: Molinari, Maria Laura. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - la Plata. Cent.de Inv En Fermentaciones Industriales (i); Argentina

Baclofen-induced reductions in optional food intake depend upon food composition

Baclofen reduces intake of some foods but stimulates intake or has no effect on others. The reasons for these differences are not known. The present study examined effects of baclofen when composition, energy density, preference, presentation and intake of optional foods varied. Semi-solid fat emulsions and sucrose products were presented for brief periods to non-food-deprived rats. In Experiment 1, fat and sucrose composition were varied while controlling energy density. In Experiment 2A, schedule of access and the number of optional foods were varied. In Experiment 2B, the biopolymer (thickener) was examined. Baclofen reduced intake of fat and/or sugar options with different energy densities (1.28–9kcal/g), when presented daily or intermittently, and when intakes were relatively high or low. However, the efficacy of baclofen was affected by the biopolymer used to thicken the options: baclofen had no effect when options were thickened with one biopolymer (3173), but reduced intake when options were thickened with another biopolymer (515). Baclofen failed to reduce intake of a concentrated sugar option (64% sucrose), regardless of biopolymer. Based upon these results, caution is urged when interpreting results obtained with products using different thickening agents. Systematic research is needed when designing products used in rat models of food intake.

Synthesis and spectroscopic investigations of hydroxyapatite using a green chelating agent as template

Hydroxyapatite [Ca10(PO4)6(OH)2, HAP] particles have been successfully synthesized by a cost-effective, eco-friendly green template method using natural and commercially available sucrose as a chelating agent. The sucrose used in this method has been extracted from various sources, three from natural and one from commercially available sources are exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology. Spectral characterizations involving Fourier transform infrared spectroscopy (FT-IR) for the functional group analysis of sucrose and HAP; carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) for the identification of the carbon atoms in sucrose and in HAP; liquid chromatography/mass spectrometry (LC–MS) for the determination of the hydrolyzed products of sucrose; and X-ray diffraction (XRD) techniques for the phase identification of the HAP particles were performed. The morphology of the HAP particles were assessed thoroughly using a scanning electron microscope (SEM) equipped with energy dispersive X-ray analysis (EDAX). The experimental results indicate that the obtained HAP using the natural sucrose as a chelating agent is of phase pure, with a well defined morphology having discrete particles without any agglomeration than the HAP from commercially available sucrose. Further, the reduced particle size can be achieved from the stem sugarcane extract as the source of the chelating agent.

Characterization of Saccharum Species Germplasm for Starch Content

The renewed interest in wild Saccharum species germplasm across sugarcane breeding programs has been necessitated by the need to widen the genetic base of breeding populations. Modern sugarcane cultivars were derived from inter-specific hybridization between S. officinarum and S. spontaneum. Very few genotypes were used in the initial hybridization event in 1900s resulting in narrow genetic diversity in modern sugarcane cultivars. Characterization of genotypes in the Saccharum collections would aid its utilization. Starch is considered as an impurity in sugarcane juice because it adversely affects the quantity and quality of sugar products, refining processes and is negatively associated with sucrose content. Therefore knowledge about the starch content of S. spontaneum and other related species would be of interest to breeders. The objective of this study was to characterize the United States of America (USA) sugarcane wild germplasm and related species for starch content. The juice samples used in this study were collected at the United State Department of Agriculture, Agricultural Research Services (USDA-ARS) Sugarcane Research Station at Houma, Louisiana; Canal Point and Miami, Florida germplasm collections. There were highly significant (P<0.001) differences in starch content among species and genotypes within species. There was a non-discrete distribution for starch within the species providing an opportunity for identifying low starch genotypes for use in germplasm enhancement programs. S. spontaneum genotypes produced the greatest variability for starch providing an opportunity for identifying low starch genotypes for use as parents. Cultivated species such as S. officinarum and S. robustum produced low starch indicating that low starch offered advantages for sucrose production. The results of this study would be more useful for parent selection within germplasm for introgression breeding.

Metabolic profiling in the roots of coffee plants exposed to the coffee root-knot nematode, Meloidogyne exigua

To understand the effect of nematode Meloidogyne exigua infestation on coffee plants, resistant and susceptible coffee seedlings were inoculated with second-stage juveniles of M. exigua, and root metabolites were studied for four time intervals at 0, 24, 48 and 96 h. During this important period for parasite establishment, the concentrations of phenols, carbohydrates, amino acids and alkaloids in the roots were measured, and hydrogen nuclear magnetic resonance spectra of the root extracts were used to identify and quantify other metabolites. One of the most striking changes was the concentration of fumaric acid on resistant plants, which varied from 59 μg g(of root)−1 to 138 μg g(of root)−1 during the first 24 h of the nematode inoculation. The same level of variation was observed much later (96 h) in susceptible plants. Similarly, formic and quinic acid concentrations increased more rapidly in the resistant plants compared to the susceptibles. Sucrose concentrations increased to 370 % in the first 48 h in the resistant plants but showed no significant variation in the susceptible plant. Besides, the concentration of alkaloids was much higher at 24 and 48 h in the susceptibles compared to the resistant plants. These results suggest that the higher production of sucrose as well as formic, fumaric and quinic acids, and the lower production of alkaloids by the resistant cultivar in the first 48 h after the nematode inoculation are associated with the resistance of coffee plants to M. exigua.

Different sodium salts cause different solute accumulation in the halophyte Prosopis strombulifera

The success of Prosopis strombulifera in growing under high NaCl concentrations involves a carefully controlled balance among different processes, including compartmentation of Cl(-) and Na(+) in leaf vacuoles, exclusion of Na(+) in roots, osmotic adjustment and low transpiration. In contrast, Na(2) SO(4) causes growth inhibition and toxicity. We propose that protection of the cytoplasm can be achieved through production of high endogenous levels of specific compatible solutes. To test our hypothesis, we examined endogenous levels of compatible solutes in roots and leaves of 29-, 40- and 48-day-old P.strombulifera plants grown in media containing various concentrations of NaCl, Na(2) SO(4) or in mixtures of both, with osmotic potentials of -1.0,-1.9 and -2.6 MPa, as correlated with changes in hydric parameters. At 24 h after the last pulse plants grown in high NaCl concentrations had higher relative water content and relatively higher osmotic potential than plants grown in Na(2) SO(4) (at 49 days). These plants also had increased synthesis of proline, pinitol and mannitol in the cytoplasm, accompanied by normal carbon metabolism. When the sulphate anion is present in the medium, the capacities for ion compartmentalisation and osmotic adjustment are reduced, resulting in water imbalance and symptoms of toxicity due to altered carbon metabolism, e.g. synthesis of sorbitol instead of mannitol, reduced sucrose production and protein content. This inhibition was partially mitigated when both anions were present together in the solution, demonstrating a detrimental effect of the sulphate ion on plant growth.

Produção de biomassa, de açúcar e de proteína em função de variedades de cana e de adubação fosfatada

The sugarcane is a fodder that presents nutritional limitations, due to low levels of protein, phosphorus and sulfur; however, the phosphorous fertilization can improve its nutritional quality, because it influences in the absorption and the metabolism of nitrogen and phosphorus. In this study, the accumulation of dry substance from phosphorus and raw protein and the production of sucrose from two sugarcane varieties in function of the phosphorous fertilization in the sugarcane – plant cycle were evaluated. The study was a 2 x 6 factorial, consisted of two sugarcane varieties, RB867515 and RB92579, and six doses of phosphorus: zero, 30, 60, 90, 120 and 150 kg ha-1 of P, with treatments distributed in blocks at random, with five repetitions. Nitrogen and potassium fertilization in doses equivalent to 100 and 200 kg ha-1 of N and K were also used respectively. The phosphorous fertilization influenced in the accumulation of dry substance and sucrose, having a quadratic effect. There was a linear effect, but discrete, of the doses of P on the concentration of this element in the dry substance, which was not observed for the raw protein concentration. On the other hand, the protein and phosphorus mass were significantly influenced by the fertilization.

Fructose Sweetens the Deal

Physiology Glucose, a metabolic product of dietary sucrose, triggers pancreatic beta cells to release insulin, which in turn allows many different cells types to take up glucose to store or use as energy. The other breakdown product of sucrose is fructose, and Kyriazis et al. report that it too

Screening Saccharum Barberi and Sinense Accessions for Flood Tolerance and Biomass Production

AbstractThis study evaluated the biomass production potential of Saccharum barberi (Jeswiet) and Saccharum sinense (Roxb. Amend. Jeswiet) accessions under short‐term flooded conditions. Plots were arranged in a completely randomized design with 20 S. sinense and 29 S. barberi accessions, two flood durations with non‐flooded controls and three replications of each treatment. There were no significant flood effects. However, in two individual accessions, ‘China’ and ‘Lu Cane’, sucrose production increased with additional flooding. The plant cane produced larger plants with a greater percentage of fibre and sucrose. Higher Brix values were obtained with the ratoon crop. Brix and fibre were negatively correlated with stem diameter. Stem length in S. barberi was the only physical characteristic that was correlated with sugar factors Brix and optical rotation. S. barberi accessions had high loadings for variables associated with sugar production and stem length, and fibre had moderate loadings for factor 1. Factor 1 explained 35 % of variance in the data. The second principal factor revealed high loadings for variables associated with plant size. Factor 2 explained 30 % of the proportional and together with Factor 1 explained 65 % of the cumulative variance in the data. Several accessions with low sucrose, high plot weight and low fibre were identified. These accessions make attractive selections in breeding for biomass production.

Rerouting Carbon Flux To Enhance Photosynthetic Productivity

The bioindustrial production of fuels, chemicals, and therapeutics typically relies upon carbohydrate inputs derived from agricultural plants, resulting in the entanglement of food and chemical commodity markets. We demonstrate the efficient production of sucrose from a cyanobacterial species, Synechococcus elongatus, heterologously expressing a symporter of protons and sucrose (cscB). cscB-expressing cyanobacteria export sucrose irreversibly to concentrations of >10 mM without culture toxicity. Moreover, sucrose-exporting cyanobacteria exhibit increased biomass production rates relative to wild-type strains, accompanied by enhanced photosystem II activity, carbon fixation, and chlorophyll content. The genetic modification of sucrose biosynthesis pathways to minimize competing glucose- or sucrose-consuming reactions can further improve sucrose production, allowing the export of sucrose at rates of up to 36.1 mg liter(-1) h illumination(-1). This rate of production exceeds that of previous reports of targeted, photobiological production from microbes. Engineered S. elongatus produces sucrose in sufficient quantities (up to ∼80% of total biomass) such that it may be a viable alternative to sugar synthesis from terrestrial plants, including sugarcane.