Inhibition of methanogenesis to control wood boring insects and pestilence

Abstract

A method for inhibiting methane production in the digestive tract of methanogenic Archaea (e.g., termites, other wood boring pests). The inhibiting of the critical biochemical pathways specific to the methanogenic Archaea is achieved by having the methanogenic Archaea ingest an anti-methanogenic compound. The anti-methanogenic compound may include, for example, naturally-occurring statins or derivatives thereof, linoleic acid or related compounds, essential oils, or some combination thereof. The naturally-occurring statins can be found in the red yeast rice extract or related biomass. As a result, the effectiveness of the methanogenic Archaea to produce methane is compromised, which subsequently results into the malfunctioning of the xylophages' digestive system. This provides a safe, natural, green and sustainable means of controlling many pests such as the Asian Beetle, Emerald Ash borer, Weevils, Deathwatch Caterpillars, and termites.

Claims

1. A method for disrupting digestive processes, communication methods and life-cycle of wood boring insects, the method comprising: inhibiting methanogenic microbial population within the wood boring insects' gut by having the wood boring insects' ingest an anti-methanogenic compound including one or more naturally-occurring statins or derivatives thereof.

2. The method of claim 1, wherein the wood boring insects include termites, Emerald Ash Borers, beetles, and ants.

3. The method of claim 1, wherein the anti-methanogenic compound includes red yeast rice to provide the one or more naturally-occurring statins.

4. The method of claim 1, wherein the anti-methanogenic compound is incorporated into a wood boring insect bait.

5. The method of claim 1, wherein the anti-methanogenic compound is incorporated into cellulose based building materials.

6. The method of claim 1, wherein the anti-methanogenic compound is incorporated into a spray.

7. The method of claim 1, wherein the anti-methanogenic compound is incorporated into a cellulose-based powder.

8. The method of claim 1, wherein the anti-methanogenic compound is combined or used individually with species and/or behavior specific pheromones.

9. A method for disrupting digestive processes, communication methods and life-cycle of wood boring insects, the method comprising: providing a food source for the wood boring insects that includes an anti-methanogenic compound, wherein the anti-methanogenic compound includes red yeast rice and inhibits methanogenic microbial population within the wood boring insects' gut.

10. The method of claim 9, wherein the red yeast rice is to provide one or more naturally-occurring statins.

11. The method of claim 9, wherein the providing a food source includes at least some combination of providing a wood boring insect bait, incorporating the anti-methanogenic compound into cellulose based building materials, incorporating the anti-methanogenic compound into a spray that is applied to the wood boring insects food source, and incorporating the anti-methanogenic compound into a cellulose-based powder that is applied to the wood boring insects food source.

12. The method of claim 9, wherein the anti-methanogenic compound is combined or used individually with species and/or behavior specific pheromones.

13. The method of claim 9, wherein the wood boring insects include termites, Emerald Ash Borers, beetles, and ants.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a gut of a termite and reaction chains that are taking place therewithin.

(2) FIG. 2 identifies known reductive reactions that occur in the gut of the termites.

(3) FIG. 3 illustrates a carbohydrate metabolism in wood and litter feeding termites.

(4) FIG. 4 illustrates the results of studies showing a large variations in amount of methane produced for different species.

(5) FIG. 5 illustrates the annual emissions of methane and carbon dioxide in the atmosphere by termites that have been calculated by various researchers.

(6) FIG. 6 illustrates a termites life cycle.

(7) FIG. 7 is a table that lists the volume of biogas production, pH values, and the concentrations of COD, ORP, and TDS measured in the Control and Test reactors during the studies.

(8) FIG. 8 is a table that lists the methane content measured in the biogas generated in the reactors during the 17-day study period.

(9) FIG. 9 is a graph of the methane concentrations listed in FIG. 8.

(10) FIG. 10 is a table that lists the methane content measured in the biogas generated in the reactors during the 19-day study period.

(11) FIG. 11 is a table that defines the tests performed for different essential oils.

(12) FIGS. 12-14 are tables showing the results of the FIG. 11 tests for the 3 time intervals (day 3, day 7 and day 12 respectively).

(13) FIG. 15 is a graph showing the results for the tests of FIG. 11 for the different time intervals.

(14) FIG. 16 illustrates an example feed bait process. The process starts in (A) where a bait station 100 is located in the ground 110. A monitoring device 120 is then paced into the ground 110 within the bait station 100. A station cover 130 is then placed on top. The process then flows to (B) where termites discover and occupy the monitoring device 120 in the bait station 100. The paths that the termites follow to get to the monitoring device 120 are illustrated as 150. The process then continues in (C) where the monitoring device 120 is removed and replaced with bait 140. The termites 155 from the monitoring device 120 are then placed on the bait 140 in the bait station 100 as illustrated in (D).

DETAILED DESCRIPTION

(15) Methane fermentation is a versatile biotechnology capable of converting almost all types of polymeric materials to methane and carbon dioxide under anaerobic conditions. This is achieved as a result of the consecutive biochemical breakdown of polymers to methane and carbon dioxide in an environment in which a variety of microorganisms which include fermentative microbes (acidogens); hydrogen-producing, acetate-forming microbes (acetogens); and methane-producing microbes (methanogens) harmoniously grow and produce reduced end-products. Anaerobes play important roles in establishing a stable environment at various stages of methane fermentation.

(16) The methanogenic Archaea (methanogens) occupy a variety of anaerobic habitats, where they play essential roles in the conversion of hydrogen and other intermediates to methane. Most species are capable of reducing carbon dioxide (CO.sub.2) to a methyl group with either a molecular hydrogen (H.sub.2) or formate as the reductant. Methane production pathways in methanogens that utilize CO.sub.2 and H.sub.2, involve specific methanogen enzymes, which catalyze unique reactions using unique coenzymes.

(17) Several cofactors are involved in biological methane formation. Coenzyme B (HS-CoB, 7-mercaptoheptanoylthreonine phosphate) and coenzyme F.sub.420 (a 5-deazaflavin derivative with a mild point potential of 360 mV) function as electron carriers in the process of methanogenesis. F.sub.420 is the central electron carrier in the cytoplasm of methanogens, which replaces nicotinamide adenine dinucleotides in many reactions.

(18) Methanogenesis from H.sub.2+CO.sub.2, formate, methylated C.sub.1-compounds and acetate, proceeds by a central, and in most parts reversible pathway. When cells grow on CO.sub.2 in the presence of molecular hydrogen, carbon dioxide is bound to methanofuran (MFR) and then reduced to formyl-MFR. This endogenic reaction is driven by the electrochemical ion gradient across the cytoplasmic membrane. In the next step the formyl group is transferred to H.sub.4MPT and the resulting formyl-H.sub.4MPT is stepwise reduced to methyl-H.sub.4MPT. Reducing equivalents are derived from reduced F.sub.420 (F.sub.420H.sub.2), which is produced by the F.sub.420-reducing hydrogenase using hydrogen as a reductant. Furthermore, F.sub.420H.sub.2 is the electron donor for F.sub.420H.sub.2-dependent methylenetetrahydromethanopterin dehydrogenase (Mtd), one of two enzymes that reduce methenyl-H4MPT. The other enzyme, H.sub.2-dependent methylenetetrahydromethanopterin dehydrogenase (Hmd), uses H.sub.2 directly. mRNA abundance for mtd increased markedly under hydrogen-limited growth conditions, suggesting that Mtd may be more important when H.sub.2 is limiting.

(19) Sharma et al. (2011) determined a 3D model structure of the F.sub.420-dependent NADP oxidoreductase enzyme from M. smithii. Based on their protein model, they detected that these residues are making a ligand binding site pocket, and they found that ligand F.sub.420 binds at the protein cavity. The inhibitor compounds lovastatin and compactin (mevastatin) show more affinity for the model protein as compare to the natural ligand F.sub.420. They share the same cavity as by F.sub.420 and surround by similar residues. Therefore, the inhibitor compounds lovastatin and compactin (mevastatin) were very effective in blocking the activity site for methane production since the enzyme was unable to bind with the substrate, resulting in decreased methane production.

(20) Monacolin K, as an example statin, can also inhibit methanogenic archaea because cell membrane production in archaea shares a similar pathway with cholesterol biosynthesis (Miller and Wolin, 2001). More specifically, bacterial cell walls are predominantly comprised of murein (peptidoglycan). Archaea, however, do not produce murein; rather, their cell walls are composed of various sulfated-heteropolysaccharides, proteins and glycoproteins/lipids along with pseudomureina structural analogue of mureinwhich is biosynthesized via activity similar to that of HMG-CoA reductase which yields cholesterol in humans.

(21) In the presence of a statin, HMG-CoA reductase is inhibited, pseudomurein biosynthesis pathway is interrupted, and methanogens are restricted from growth and proliferation. And since methanogens are so uniquely different than bacteria, the inhibitory effect of statins is not observed in microbes.

(22) The compound 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, is another enzyme that is very critical in methane production, and Archaea are the only bacteria known to possess biosynthetic HMG-CoA reductase (Miller and Wollin, 2001). Garlic oil has been hypothesized to inhibit the biosynthesis of HMG-CoA (Busquet et al., 2005; Fraser et al, 2007). At higher concentrations, various essential oils have exhibited wider range anti-microbial activity so the dosage and applications strategies are wide and variable.

(23) Anti-methanogenic compounds are compounds designed to inhibit methane production in environments where methanogens are established and active. It is believed that anti-methanogenic compounds could inhibit the methane production in the gut of termites and other wood-boring and cellulose digesting pests. Limiting the production of methane causes dysfunctioning of the pests' digestive system thus impeding their growth and development. The impediment of their growth and development would thus make this an effective non-toxic method of controlling termites and other similar pests.

(24) Anti-methanogenic compounds may include one or more unique compounds that either alone or in combination with one another effect the production of methane. Red yeast rice is believed to be an anti-methanogenic compound. In order to determine the effectiveness of red yeast rice for inhibiting methane, two bench scale studies were performed.

(25) Laboratory Study 1

(26) Two anaerobic reactors were utilized, a control and a test reactor. The two reactors were seeded with biomass treating expired dietary supplement, which contained an active methanogenic population. The reactors were fed once per week, and were operated as anaerobic sequencing batch reactors.

(27) During the first week of startup, the reactors contained only the methanogenic culture, without soil. After one week, silty sand was added, resulting in a slurry having a solids concentration of 20% by weight. The reactors were operated for another week with the silty sand, to ensure that the sand did not affect methanogenic activity. The bioreactors were 2.5 L in volume, containing 2 L of slurry. The reactors were airtight and were especially designed for anaerobic reactions. The reactors were maintained at laboratory temperature 22 C.-24 C. The reactors were operated by feeding with dietary supplement once a week. The target initial chemical oxidation demand (COD) concentration after feeding was 2000 mg/L.

(28) Throughout the week, the volume of biogas produced was measured as follows. A syringe was inserted periodically into a septum-filled port in the top of the reactor to collect a gas sample for methane content. The methane content of the biogas samples was then quantified by injecting into a gas chromatograph with a flame ionization detector (GC-FID). The reactors had dedicated probes to measure pH and oxidation reduction potential (ORP). After each cycle (i.e., before feeding), a probe was inserted into the reactor to measure total dissolved solids (TDS), and a sample was collected to measure COD. The mixer was turned off during sampling and feeding to minimize the introduction of oxygen into the reactor contents.

(29) The test reactor was initially dosed with a 40 g/L concentration of red yeast rice. One week later the control was dosed with 20 mg/L red yeast rice.

(30) Laboratory Study 2

(31) Two test aliquots were prepared under a nitrogen atmosphere in a glove box as follows: (1) a 240 mL amber glass screw-cap septum bottle was filled with 100 g of dry soil (70 mL); (2) deoxygenated deionized water was slowly added to the soil to saturate the soil; an additional 40 mL of water was then added to the soil; and (3) manure slurry was added to yield a 1 weight percent manure dose to the soil.

(32) Once the bottle was sealed it was removed from the glove box. The soil was kept in the dark (by wrapping with foil) at room temperature (22 C.). A needle connected to a polyethylene tube was pushed through the bottle septum and the tube outlet was placed in an inverted graduated cylinder in a water bath. The gas generation rate was recorded as the water was displaced over a period of 10 days.

(33) The methane reduction trial included two sample formulations, with and without red yeast rice, for a total of 4 samples. The bottles were sampled 0.5, 1.5, 5, 12, and 19 days following the sample preparation.

(34) Results for Laboratory Study 1

(35) The first two weeks of the studies were the startup period, and the second two weeks were the test period. The startup period established the methanogenic population in the two reactors. During the first week of startup, the reactors were operated without the silty sand, and the second week they were operated with the silty sand (20% by weight). The test period started with the dosing of the test reactor with red yeast rice (40 g/L). During the first week of the test period the control was maintained as a proper control, with no red yeast rice added. Because the 40 mg/L dose of red yeast rice reduced methane production in the test reactor, it was decided to dose the control reactor with 20 g/L of red yeast rice during the second week of the test period. The test period lasted 17 days.

(36) FIG. 7 is a table that lists the volume of biogas production, pH values, and the concentrations of COD, ORP, and TDS measured in the control and test reactors during the studies. The volume of biogas produced each feed cycle (i.e., each week) in the reactors ranged between 72-82 mL. It is notable that the volume of gas was not affected by the introduction of silty sand during week 2 of the startup period. The addition of 40 mg/L of red yeast rice to the test in the first week of the test period and the addition of 20 mg/L of red yeast rice during the second week of the test period did not appreciably impact biogas volume in the reactors. The COD measurements after each sequencing batch reactor cycle ranged from 56 to 108 mg/L. The reactors were fed 2000 mg/L each cycle, so the COD concentrations in FIG. 7 demonstrate that the COD was consumed by the anaerobic culture. Values of pH ranged between 6.1 and 6.4. Values of ORP were all close to 300 mV, which is typical of methanogenic conditions. The TDS in the reactors ranged from approximately 1200 to 1250 mg/L.

(37) FIG. 8 is a table that lists the methane content measured in the biogas generated in the reactors during the 17-day test period.

(38) FIG. 9 is a graph of the methane concentrations listed in FIG. 8. During the Startup Period, methane concentrations varied from approximately 55% to 70%, which indicates an active methanogenic culture. The red yeast rice dose of 40 mg/L in the Test reactor reduced the methane content of biogas from 62% to below detection (0.05%) after 11 days. The methane concentration remained below detect in the Test reactor until day 17, when the reactors were dismantled. The red yeast rice dose of 20 mg/L in the Control reactor on day 7 reduced the methane content of biogas from 65% to below detection (0.05%) by day 17 (i.e., after 10 days). During the Test period, the volume of biogas produced in the Test and Control reactors did not change appreciably only the methane concentration of the biogas was changed.

(39) Results for Laboratory Study 2

(40) FIG. 10 is a table that lists the methane content measured in the biogas generated in the reactors during the 19-day study period. The first soil formulation (SF1) that contains 20% of the red yeast rice (approximately 40 mg/L in solution) showed great effectiveness in inhibiting the methane production by 96% during the 19-day sampling interval. Similarly at the same time fragment the second soil formulation (SF2) resulted into a 25% decrease in methane production.

(41) The above tests clearly illustrate the effectiveness of red yeast rice in inhibiting methane. By contacting the termites with red yeast rice (e.g., having the termites digest the red yeast rice) it is believed that this would provide a green, organic and non-toxic (to humans) way to control damage and pestilence induced by wood-boring insects that harbor methanogens in order to digest or metabolize cellulose.

(42) Utilizing organic statins (some of which can be present in red yeast rice extract as well as biomass of other organisms) may inhibit the methanogenic enzyme and coenzyme systems essential to the growth and development of wood-boring insects. Thus disrupting their digestive tracts/life-cycle stages by limiting their effectiveness in producing methane and causing dysfunctioning of the pests' digestive system thus impeding their growth and development.

(43) Essential oils are also believed to be an anti-methanogenic compound. Laboratory studies were performed to comparatively evaluate the anti-methanogenic potential of multiple essential oils (e.g., Garlic Oil [GO], Cinnamon Bark Oil [CO], Cinnamon Bark Powder containing 4% CO [CB] and lemongrass Oil [LO]).

(44) Laboratory Study 3

(45) Manure and groundwater samples were collected from a site in Monticello, Wis. at 1:1 ratio. The collected samples were added to 125 mL amber glass bottles equipped with PTFE-lined open septum caps (VOA vials). The testing program included 40 vials each filled with 20 g manure slurry and 20 g groundwater. All samples were sacrificial and disposed after completion of the analyses. Five (5) vials were used to indicate the onset of anaerobic conditions by measuring pH, ORP and methane over a 2-week period.

(46) FIG. 11 is a table that defines the tests performed. A total of 27 vials were prepared to analyze the 9 tests defined in FIG. 11 over 3 time intervals (day 3, day 7, day 12). Finally 8 vials were setup as replicate samples.

(47) Gas samples from the sample container headspace were analyzed for methane in the gas phase using a gas chromatograph (GC) with a flame ionization detector (FID). After these analyses were completed, pH and ORP were also measured.

(48) FIGS. 12-14 are tables showing the results of the 9 tests for the 3 time intervals (day 3, day 7 and day 12 respectively). FIG. 15 is a graph showing the results for all the tests for the different time intervals. As illustrated, it is apparent that all essential oils were successful in decreasing the amount of methane produced, with the Garlic Oil [GO] appearing to be the most effective of all.

(49) As a termite xylophagous termite grows and develops, methanogens clearly play an integral role in the reproduction, growth, development and overall activity of the organism. The microbes play similar roles in the life-cycles of other wood-boring insects and cellulose consumers such as xylophagous beetles. As such, the anti-methanogenic compounds (e.g., red yeast rice, essential oils) could be utilized to control termites and all other wood-boring and cellulose digesting pests including but not limited to: i) the Emerald Ash Borer, ii) weevils, iii) wood-boring caterpillars (Lepidoptera) such as Carpenterworms (Prionoxystus robinae), and iv) wood-boring Bostrichidae beetles (formerly referred to as the family Lyctidae). The socioeconomic cost and destruction caused by such organisms is significant, and a means to control them using safe, natural, sustainable means is of great benefit to society.

(50) The anti-methanogenic materials, described herein, can be applied in a myriad of ways (feed baits, aerial applications, dustings, coatings, pellets, powders) at various stages of the targeted organisms life cycle to yield effective treatment under various scenarios. The feed baits, aerial applications, dustings, coatings, pellets, and/or powders could be applied to locations where the pests are known to inhabit or feed. According to one embodiment, the anti-methanogenic compound is incorporated into cellulose based building materials.

(51) FIG. 16 illustrates an example feed bait process.

(52) By controlling the activity of methanogens as disclosed, this provides a unique and important means of pest management.

(53) It is understood that the invention is not limited to the disclosed embodiments and examples, but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.