Acetoin (3-hydroxy-2-butanone) is a four-carbon ketone–alcohol used in the food industry and is also a precursor to important industrial chemicals such as butanediols and butanols. It is used in the food industry for the production of several foods and beverages and in the cosmetic industry to confer a desirable aroma. Sugars produced by sugar beets and sweet sorghum were evaluated for microbial conversion to acetoin, as a potentially cost-effective alternative to synthetic production of acetoin. This is our preliminary work with sugar beet and sweet sorghum sugars as starting materials for the production of acetoin using the bacterium Bacillus subtilis. The results show that the compound was produced at a maximal concentration of 6% (weight/volume) following the conversion of the diluted sugar crop syrups.

For large-scale manufacture of biofuels and bioproducts from sweet sorghum (Sorghum bicolor L. Moench) biomass feedstocks, the long-term storage of 65 Brix (% dissolved solids) syrups is urgently needed for year-round supply and operation, efficient transport, and acceptable end-product yields. Shorter-term storage of lower Brix syrups is also required for direct fermentation. Three unsaturated, inexpensive, and readily available vegetable oils were preliminary evaluated as surface sealants (0–1.7 cm-deep layers) on stored 65 Brix sweet sorghum syrups at 25 °C. Compared to no sealant, soy bean, canola, and sunflower oil sealants preserved the 65 Brix syrups for up to 1 year. There was generally a strong surface oil layer effect, with 1.7 cm-deep layers providing the most significant (P < 0.05) protection. Soy bean oil (up to 0.5 cm) did not preserve 28 Brix syrups against severe microbial deterioration over 7 days of storage. More replicated studies are now needed to validate the results.

Sweet sorghum bagasse is the solid fibrous product that remains after sweet sorghum stalks are crushed to remove juice. It can be reapplied to the field to enhance the productivity of subsequent crops as a soil amendment. The majority of sweet sorghum bagasse remains underutilized because more is produced than can be practically applied to fields. Accumulation of bagasse is increasing due to increased sweet sorghum production for the primary product, juice. The by-product, bagasse, has potential for novel uses, but it must be stabilized for conversion outside harvest season. It is not feasible to process bagasse while time and equipment are invested in harvesting the mature crop. This study determined whether compacting and ensiling sweet sorghum bagasse prevented degradation for processing after harvesting, when resources are available in more amount. It was found that ensiling bagasse limited microbial degradation of the material and stabilized the physicochemical properties that will be beneficial for fuel, feed, and other uses.

Soil amendments are used to improve soil quality, thereby enhancing plant growth and health. Efforts have been made to replace synthetic chemical enhancers. It is also preferable to not use natural products such as peat moss, the harvesting of which can be harmful to marine ecosystems. Viable replacements include worm castings, which can contribute beneficial microbes, as well as physicochemical amendments. Another potential soil amendment is the compost produced from sugarcane processing byproducts. While the texture of these two materials is not ideal for even dispersal onto fields, the addition of biochar improves the texture. Previous work demonstrated that blending them with biochar from sugarcane byproducts added physicochemical benefits, while not quantitatively reducing the microbial load, even after storage. Microbial populations of the blends in the present study were found to (1) contain taxonomic groups that contribute to plant health and (2) not contain human pathogens. Based on the quantitative and qualitative microbial analyses, it has been determined that 50% or less biochar in a blend will allow maintenance of beneficial microbes in stored samples.

The environment of a sugar factory is conducive to the propagation of microbes that are introduced with the harvested crop. Further introductions are made from the machinery surfaces and water during processing. Each microbe type has a preferred range of temperature and water activity, so a factory may have different populations in different areas. It is important to detect microbial presence so appropriate control measures can be taken, and to conserve expenses when treatment is not needed. The most ideal detection methods in a factory will yield accurate results quickly and inexpensively. A mannitol detection method has been developed for the sugarcane industry, and subsequently applied to sweet sorghum and sugar beet. Conversion of sugar crop byproducts, such as bagasse, are a potential new value stream. An analysis was conducted to determine whether environmental conditions and the presence of microbes in bagasse affects the chemical composition, and subsequent application for novel uses. Fuel value was found to be negatively affected when bagasse was left uncovered and exposed to sun and rain. The fuel characteristics were maintained. Bagasse was also successfully pelletized and converted to biochar for stable storage and transport.

With sweet sorghum production and subsequent accumulation of bagasse on the rise, it is important to look for novel uses for its by-products. Bagasse, the solid fibrous product left after sweet sorghum stalks are crushed to remove juice, is partially reapplied to the field to enhance subsequent crops. The majority of bagasse remains largely underutilized because more is produced than can be practically applied to fields. This study determined sweet sorghum bagasse chemical and microbiological properties for use as a fuel source. It was determined that sweet sorghum variety had no major effect on fuel value. Microbes have the potential to consume sugars and other beneficial compounds in bagasse, but our analysis of microbial counts showed that microorganisms did not reduce the fuel value of the bagasse tested. Sweet sorghum bagasse was also found to have favorable fuel value when compared to sugarcane bagasse, due to its lower ash and higher fixed carbon contents.

Sugarcane sucrose deterioration begins post-harvest causing significant problems for the sugar industry. In Louisiana, the majority of sucrose destruction occurs during storage in mill yards and truck sleeper loads. Raw sugarcane factories in Louisiana apply biocides to reduce sucrose loss caused by bacterial contamination. However, very few factory studies have evaluated biocide usage, and no known studies have included cane grinding rates. During cane juice processing at two Louisiana raw sugar factories this study assessed three biocides, sodium hypochlorite (bleach), carbamate and humulone (hops) using cane grinding or juice flow rates by integrating factory tank and pipe retention times as sampling intervals. Processed juice exposure to biocide was calculated at less than 10 minutes. Results showed that bleach reduced microorganism growth by two logs. Carbamate and humulone application had no effect on growth, but microbe concentration varied with juice temperature, and the largest microbe reduction occurred during juice clarification. Currently, discontinuing usage of carbamate, humulone and bleach is not recommended. More research is needed in the area to determine if biocide application is practical and effective during factory operation. Study findings emphasize the increased need for consistent, rigorous factory and mill yard sanitation.

Sweet sorghum bagasse is an untapped resourceful carbon-rich material that can be thermochemically converted into value-added biochars. These biochars can be applied to the field as soil amendment for soil health enhancement, improved soil carbon content, water holding capacity, soil drainage and aeration, and plant and sugar yields. This study looked at four different varieties of sweet sorghum and processed their bagasse into biochars at low and high temperature (350 °C and 700 °C). The feedstock materials and respective biochars were chemically characterized for their nutrient content. Several physicochemical and adsorptive properties were also determined to ascertain their potential use as either adsorbents, soil amendment materials or as fuel sources, and compared with other plant and refinery wastes. No major differences were observed among the varieties in terms of resulting properties of the biochar; however, pyrolysis temperature affected biochar properties. Fuel value, fixed carbon, ash content and surface area increased with pyrolysis temperature. However, low-temperature biochars were better candidates as copper ion sorbents. Benefits of using sweet sorghum bagasse as value-added material are expected to help both sweet sorghum growers and processors through the production of value-added pyrolysis products, as well as enhancing the sweet sorghum industry’s role in renewable energy markets.

this study investigates Isaria fumosorosea (Ifr) infection of and transfer among Formosan subterranean termites (FST). Prior to fungal exposure nestmates were fed Nile Blue, dye or Neutral Red dye. Blue FST were exposed to 6.3 x 109 fungal spores and mixed with red nestmates. At timepoints up to 168 h, termites were removed from each dyed group and fixed with osmium tetroxide. SEM observation at 24 h post-exposure showed most fungal conidia ungerminated and on the external cuticle of blue FST. At 48 h, germ tubes had formed on blue FST and penetrated the cuticle. Hyphae were observed externally at 96 h post-exposure. Fungal spores were visible on red FSt 96 h after placement with blue FSt, and hyphae were abundant at 168 h post-exposure. Blue FST were fixed, dehydrated, then embedded with a low viscosity epoxy. Embedded FST were sectioned with a microtome and visualized via light microscopy. Ifr penetrated the cuticle of blue FST at 48 h and were found on the interior of termites after 72 h. Transfer to red FST was confirmed 96 h post-exposure through visualization of spores.

Sugarcane bagasse is a potential source for commercially-viable products such as animal feed, mulch, or fuel. The applications will be determined by the levels of moisture, ash and beneficial chemicals in the bagasse. Manufacturing value-added products will be impacted by microbes, and may require microbial conversion of the substrate. Microbes present in bagasse have potential for conversion of bagasse to beneficial products because they have the ability to metabolize fibers, and to survive the environmental conditions in bagasse. These microbes also have the potential to interfere with the production of desired products. An analysis of both microbes and chemicals present in bagasse is necessary to determine the most viable potential applications. This study evaluates the microbial and physico-chemical properties in sugarcane bagasse samples from three different varieties in a research setting, and samples of mixed bagasse varieties at three factories. All samples were collected in south Louisiana. Stalks from individual varieties were either shredded or passed through a roller mill. The fresh mixed variety bagasse was collected from the final tandem mill at a factory. The stored mixed variety bagasse was collected from piles at the factories. Samples for microbial analysis were grown on two types of growth media. One medium, MRS, selects for Leuconostoc, Lactobacillus, and other microbes that metabolize sugars and produce degradation products. The second medium, NA, allows growth of a broad range of microbes which are present in the cane growing environment. Microbial counts and types were compared across varieties and processing methods, and were correlated with physicochemical analyses. Fuel value of bagasse was significantly reduced when the bagasse was stored uncovered.

Formosan subterranean termites (FST) were exposed to strains of Beauveria pseudobassiana (Bpb) and Isaria fumosorosea (Ifr) to determine virulence of the fungi. Once lethality was determined, sublethal doses of Bpb were combined with enzymes capable of degrading the insect cuticle to measure the potential to enhance fungal infection. Bpb applied to FST in combination with proteinases and a chitinase caused increased mortality over the fungus alone. Mortality was enhanced when Ifr was applied to FST in combination with a chitinase isolated from Serratia marcesans. A lipase isolated from Pseudomonas cepacia, when combined with Ifr, also resulted in greater mortality than all control treatments. FST were also exposed to the eicosanoid biosynthesis inhibitors (EBIs) dexamethasone (DEX), ibuprofen (IBU), and ibuprofen sodium salt (IBUNA), in combination with Ifr. Combining Ifr with IBUNA caused significantly increased mortality on days 6, 7, and 9. Cuticle-degrading enzymes and EBIs may have potential to enhance the pathogenic effect of a fungal control agent against the Formosan subterranean termite.

Strains of the entomopathogens Isaria fumosorosea and Metarhizium anisopliae were grown on PdA plates containing chitin azure to determine whether chitinase expression could be correlated with their previously measured pathogenic effects against Formosan subterranean termites. Isaria strains 3581 and 4491 formed chitin azure conversion zones that were significantly larger, 40.0 mm on day 12, than the zone formed by strain 92118, 36.8 mm on day 12. However in past studies, strain 4491 was less pathogenic than strain 92118. the zones formed by M. anisopliae strain 30905 were significantly smaller than those formed by the Isaria strains, 7.0 mm on day 12, but the Metarhizium strain is known to cause mortality of termites. to determine if the glucose in PdA inhibited chitinase expression, the experiment was repeated on A&M plates supplemented with fructose instead of glucose. More variation was seen between strains 3581 and 4491, but the expression of chitinase was not enhanced.

A potential use for sugarcane trash is conversion to mulch. This study evaluated whether a compost enhancer or nitrogen would accelerate degradation. Trash was obtained from a sugarcane grower, and treated with water only, a compost starter, and/or nitrogen at rates of 1 kg (Low) or 2 kg (High) / 10 m(2). Treatments were monitored for 21 weeks. Height of the trash, temperature and visual changes were determined. Bins that received water only had the greatest reduction in height, 54.5%. None of the treatments resulted in a change in temperature, possibly due to the mass of material in each bin. All watered bins had a greater observed change in consistency, and the low nitrogen treatment changed in color and texture in all replicates. Intact bales were also observed. Trash in the center of bales that were watered and left dry underwent changes in color and texture. While dry bales did not receive added water, they likely held sufficient moisture from rainfall allowing for conversion of the leaves. Added water was necessary for conversion of trash in the bins, and enhanced by the addition of low nitrogen. Larger masses of trash would allow temperature maintenance to potentially accelerate conversion in future studies.

Termite mortality was measured when fungi were combined with bacteria or a chemical termiticide to determine whether a synergistic effect occurred. The fungus Beauveria bassiana was combined with the non-repellant chemical termiticide imidacloprid. Of the three B. bassiana strains tested one, B. bassiana ATCC 90519, was sufficiently pathogenic on its own that the advantage of a supplementary chemical treatment was marginal. The mortality caused by another fungal strain, B. bassiana ATCC 26037, was improved in combination with imidacloprid at both of the tested chemical concentrations over the first 14 days. The remaining fungal strain, B. bassiana ATCC 90518, demonstrated an overall mortality rate in combination with imidacloprid of 82.5%, versus a rate of 65.0% for the fungus alone. The fungus Isaria fumosorosea (Ifr) was combined with the bacterium Bacillus thuringiensis (Bt). On day 5, Ifr, Bt, and the combined treatment at a 10(6) spores or cells/ml dosage caused 8.8%, 22.5%, and 15.0% mortality, respectively. The Bt and combined mortality rates are not significantly different. Control mortality on day 5 was 5.0%. On day 13 the combined 10(6) treatment mortality rate was 91.3%, which was significantly higher than all other treatments: control at 17.5%, Ifr at 36.3% and Bt at 35.0%. When Ifr and Bt were applied at a 10(9) spores or cells/ml dosage, Ifr alone caused a mortality rate of 97.5% as early as day 5. The combination with Bt could not significantly increase the effectiveness of this dosage. These data demonstrate the potential for synergistic effects of fungal and chemical treatment methods, thereby broadening the use of microbial control agents and reducing the quantity of chemical agents necessary to effect control.

Background: Two entomopathogenic fungi, Isaria fumosorosea and Metarhizium anisopliae, and one bacterium, Bacillus thuringiensis, were tested for their ability to cause mortality of Formosan subterranean termites (FST), Coptotermes formosanus (Shiraki), after liquid exposure, and for their lack of propensity to repel FST.Results: The fungus Isaria fumosorosea at 10(8) spores/ml caused 72.5% mortality on day 7, significantly higher than the control and 10(6) spores/ml treatment. On day 14, the 10(6) and 10(8) concentrations caused 38.8% and 92.5% mortality, respectively, significantly higher than the control. On day 21, 82.5% and 100% of the termites were killed by the 10(6) and 10(8) treatments, respectively. I. fumosorosea did not repel termites at 10(6) nor 10(8) spores/g in sand, soil or sawdust. The fungus Metarhizium anisopliae at 10(8) spores/ml caused 57.5% mortality on day 7, 77.5% mortality on day 14 and 100% mortality on day 21.Conclusions: On all three days the rate of mortality was significantly higher than that of the control and 10(6) spores/ml treatment with I. fumosorosea. Neither I. fumosorosea nor M. anisopliae caused repellency of FST in sand, soil or sawdust. The bacterium Bacillus thuringiensis did not cause significant mortality on days 7, 14 or 21. When termites were exposed to cells of B. thuringiensis in sawdust and when termites were exposed to a mixture of spores and cells in sand, a significantly higher number remained in the control tubes. Repellency was not seen with B. thuringiensis spores alone, nor with the above treatments in the other substrates.

Several classes of surfactants/foaming agents were screened for compatibility with blastospores of Paecilomyces fumosoroseus. The surfactants were assayed to determine their influence on the rate of germination, viability and conidia. production by the blastospores. Surfactants compatible with blastospores were then assayed for their foam forming properties using a commercially available foam generator. These tests identified keratin hydrolysate as the only suitable surfactant in terms of biocompatibility and foam forming properties. Laboratory bioassays were conducted to determine the effect of keratin hydrolysate on the efficacy of blastospores against Formosan subterranean termites. The results showed keratin hydrolysate increased the efficacy of P. fumosoroseus and suggest that this foam formulation of P fumosoroseus may be useful in controlling Formosan subterranean termites.

Alates of the Formosan subterranean termite, Coptotermes formosanus Shiraki, collected after swarming in 2002 died within 48 h, and the cadavers were visibly infected with a fungus. Fungi were picked from the cadavers, transferred to media, and ultimately isolated to purity. The individual fungal cultures were then used to infect Formosan subterranean termite workers. A single fungal isolate, C4-B, taxonomically identified as Metarhizium anisopliae (Metschnikoff), was found to cause rapid mortality of Formosan subterranean termite alates. This is the first report of a biological control agent for termite alates. In initial experiments, C4-B was more lethal to both alates and workers compared with M. anisopliae strain ESC 1, previously marketed as the termite biocontrol agent BioBlast. Dose-response assays in which Formosan subterranean termite alates were exposed to a known concentration of C4-B spores revealed that 10(6) spores/microl killed 100% of the alates in 3 d, both 10(5) and 10(4) spores/microl in 6 d, 10(3) spores/microl in 9 d, and 10(0) spores/microl in 12 d. Assays with workers demonstrated that 10(6) and 10(5) spores/microl killed 100% of the workers in 6 d. In an experiment to test the transfer of inoculum from infected workers to uninfected nestmates, 62.8% of the workers died in 21 d when only 20% of the workers had been inoculated. Mortality of alates caused by C4-B was tested at two field sites by dispersing fungal spores on grassy lawns and collecting alates from the treated areas. Alates thus infected showed 100% mortality by day 5, whereas only 64.8% of untreated control alates from the same collection area were dead on that day.

Tolerance, pathogenicity and transmission studies of the fungi Metarhizium and Beauveria, show that biological control agents can enhance termite treatment flexibility. Subterranean termites cause significant damage to wood structures and trees, especially along the Gulf of Mexico coastal region of the United States. A predominant pest species is the Formosan subterranean termite, Coptotermes formosanus (Shiraki), which differs from native termite species in increased colony density and a propensity to destroy living wood. However, in order for termite control approaches to work they must be non-repellant, transferrable, and have delayed toxicity to allow transfer from foraging workers to their nestmates. An Integrated Pest Management (IPM) approach will be necessary to reduce the impact of these pests. One component of IPM, and the focus of this work, is the development of biological control agents. Environmental conditions in FST nests and sites of infestation, such as living trees, can vary greatly. Some treatment sites require novel treatment methods which fungi may be uniquely suited to provide.

The resolution of chromosomal-sized DNAs by PFGE has many applications that include karyotyping, strain identification of similar species, characterization of transformed strains, building of linkage maps, and preparation of DNA for genomic analysis. Successful electrophoretic separation of chromosomes is an empiric process in which the initial concentration of intact chromosome-sized DNA and the optimization of electrophoretic parameters are the most important experimental variables. Nonetheless, inherent attributes of the genome architecture of certain species may thwart success. When a karyotype contains numerous chromosomes of the same size and/or many large (greater than 8 Mb) chromosomes, no amount of manipulation of the electrophoretic parameters will resolve individual chromosome bands using present technology. Further, fungi display a surprising amount of intraspecific variation in both chromosome number and size, making it difficult to establish a standard "reference" karyotype for many species. Although PFGE is not a panacea for bringing genetics to species that lack classical genetic systems, it often does provide a way for developing a molecular linkage map in the absence of a formal genetic system. It is far faster than parasexual analysis in the discovery of linkage relationships. For genomics projects, DNA can be recovered from pulsed field gels and used to prepare chromosome-specific libraries. Where whole genome sequencing strategies are used, chromosomes separated by PFGE provide an anchor for sequencing data. Electrophoretic karyotypes can be probed with anonymous pieces of DNA from bacterial artificial chromosome (BAC) contigs, thereby facilitating the building of physical maps. In conclusion, despite its shortcomings, the PFGE technique underlies much of our current understanding of the physical nature of the fungal genome.