FR2964009A1 - Method for producing e.g. mat of sod utilized for maintaining ground of gardens, involves incorporating seeds or rhizomes of sod, nitrogen source and polymer grains with water retaining, non phyto-poison and slightly biodegradable - Google Patents

Abstract

The method involves preparing a culture support formed of crushed sugar cane bagasse in which seeds or rhizomes of sod, nitrogen source i.e. ammonia source, and polymer grains with water retaining, non phyto-poison and slightly biodegradable are incorporated. The support is arranged on a plastic film. The ammonia source is produced by urea whose progressive degradation drives the formation of ammonia. The urea is incorporated by watering or dispersion of aqueous solution on the support.

Description

PROCESS FOR PRODUCING A NEW TURF CARPET AND USES THEREOF

The present patent application is in the field of the necessities of life and more particularly in the field of grounds maintenance.

It relates more particularly to a method of producing sod in patches or carpets to protect the soil against erosion caused by bad weather or mechanical interventions.

Specifically, it relates to a method of forming a carpet or turf plates or rolls consisting of a carrier consisting of sugarcane bagasse recovered from the previously milled sugar cane processing plant, wherein seeds or turf rhizomes, a source of nitrogen and grains of non-phytotoxic and non-biodegradable superabsorbent polymer are incorporated.

Sugar cane bagasse is a fibrous residue which, together with gaseous ethanol, constitutes an important waste of the sugar industry. Part of the production of this waste is recycled as a source of raw material for paper making, but industrial processing of delignification and bleaching of pulp can be harmful to the environment. In response to these constraints, researchers from IRD and INRA, 25 grouped within IFR-BAIM (Agro-industrial Biotechnologies of Marseille), have developed a new biological process that transforms bagasse into pulp while producing an enzyme of industrial interest. Its principle is based on the particular metabolism of a filamentous fungus. This one, cultured on bagasse in the presence of ethanol, produces this enzyme which destroys the lignin of the substrate, thus transforming it into pulp. The first tests carried out in the laboratory show that this integrated bioprocess can be adapted to the treatment of other fiber sources, thus opening an interesting perspective for the paper industry.

Wood is the main raw material used in the manufacture of paper pulp, 35 but the increase in demand in this sector, while forest resources are shrinking, have forced manufacturers to turn to other sources of pulp. raw materials, such as cereal straws, reeds, bamboo or sugarcane bagasse. This residue, obtained after grinding the canes, is already used as a source of paper fibers in producing countries (in South America and India for example, where it concerns 20 40% of the paper produced). This sector absorbs 10% of the world production of sugar cane bagasse, whose use combines several advantages: a fast growth of the plant, a widespread culture, a less need for energy and chemicals for the treatment of sugar cane. bagasse ... It is also a way to dispose of this important waste from the sugar industry: for a 45 ton of refined sugar, two tons of bagasse are produced. Researchers from IRD and INRA have studied an alternative biological solution.

They have just developed a non-polluting process in the laboratory, which makes it possible both to produce a delignifying enzyme (laccase) from a filamentous fungus 50 and to recycle sugarcane bagasse. Its principle is based on the particular metabolic characteristics of this fungus, Pycnoporus cinnabarinus, which naturally produces laccase. This enzyme destroys the lignin contained in the fibers of the sugarcane bagasse used here as a substrate, thus transforming it, after mechanical refining, into pulp. As the lignin disappears, the resulting paste whitens. This paste, which can be used in the state for the manufacture of cardboard, however, must undergo additional treatment based on hydrogen peroxide to produce a printing paper and writing.

P. cinnabarinus naturally synthesizes little laccase when growing on bagasse, so the addition of volatile compounds, such as ethanol, is necessary to increase laccase production under these conditions. Ethanol was selected as the inducer in this study because of its abundance, low toxicity and low cost of production. The researchers have also shown that this compound, introduced by forced convection into the system at the rate of 7 g of ethanol per m3 (concentration equivalent to 3 ° alcoholic in the liquid phase), allowed to obtain a maximum production of laccase ( 90 U per g dry bagasse), 45 times the production obtained without ethanol. It has been found, moreover, that the ethanol introduced is not or very little consumed by the fungus which preferentially uses other carbon sources, obtained from bagasse (sucrose) or introduced with this substrate (maltose, extracts of yeast...). It can therefore be recycled in the system or eliminated in a second associated system.

Reproduction of larger-scale fermentation tests in an 18-liter bioreactor confirmed the efficacy of laccase production in the presence of bagasse and ethanol (90,000 U per kg dry bagasse after 30 days). the amount needed to treat 4 kg extra bagasse without adding mushrooms). Thanks to this bioprocess, a saving of 50% of the energy consumption required for pulp refining, compared to that recorded during the refining of pulp from untreated bagasse biologically, was recorded. In addition, the paper's mechanical properties (tensile and tear resistance) were improved by 35%, without appreciable loss of material.

All these results underline the potential for applications of this bioprocess in the paper industry. The recovery of laccase at the end of the cycle, after washing and pressing bagasse, makes it possible to treat additional quantities of this substrate and, thus, , to increase the profitability of the operation. Moreover, this process can be adapted to the treatment of other raw materials (wood, cereals ...). The study of the induction of laccase production by methanol can similarly be considered in order to recycle this compound, which constitutes one of the main pollutants emitted by the paper industry.

40 Another study evaluates the different possibilities for recovering Bagasse after biological (composting) or chemical treatment (Humifert process). The optimal conditions for composting Bagasse (B) were determined in bioreactors, then deepened into a digester by measuring the physicochemical and microbiological characteristics of the substrates. 45 They involve the use of milled bagasse with residual sludge (b) (20% dry weight), rather than mineral additives (Urea-Phosphorus). The contribution of FeCl (3) to the optimal mixture makes it possible to obtain a compost enriched with NH (4) (+) and iron ions. The digester stabilization phase (10 to 22 days) is optimized when the maximum temperature of the mass is 60 ° ± 5. After several months of maturation, B-b composts have acquired interesting physicochemical characteristics for an agronomic valorisation evaluated by tests on potted plants. Despite their acidity (pH 4.7 to 6.0), they are not phytotoxic and prove to be excellent growing media, unlike BUP compost, which is still immature. The iron-enriched compost is additionally provided with an anti-chlorinating power. Treatment of bagasse with nitrogen oxides (Humifert process) in the presence of apatite makes it possible to obtain a product enriched in nitrogen and water-soluble phosphates, but phytotoxic.

Sugar cane bagasse in the full extent of current knowledge can be defined as a variable mixture of lignin, cellulose and hemicellulose. It has already been sought to reduce the lignin content by enzymatic digestion or by addition of salts to improve such a preparation and confer greater degradability in the case of a food use for animals. In this way, the possibility of digestion of this plant residue is increased and the metabolism of the main polysaccharides of the cell wall is thus increased.

The objective of the present invention is substantially different. It is above all a question of improving the cultivation of a biological support for the production of turf made in plates, in carpets or in rolls starting from a support of culture consisting of bagasse of sugar cane deposited on a plastic film disposed on the soil containing grass seeds and a source of nitrogen without the culture medium is phytotoxic but simply fungistatic.

The nitrogen source is provided by an ammonia treatment resulting from the progressive hydrolysis of urea incorporated into the bagasse carpet.

In addition, superabsorbent polymer seeds known as polyacrylamide sodium salt are incorporated into the bagasse carpet.

This product is likely to give water gradually and recharge the carpet as many times in water without the need to water with water.

This superabsorbent polymer is used in the form of crystals or grains of water to supply water to the bagasse carpet.

The use of the crystal of water makes it possible thanks to these grains retenters of water, to save watering while promoting the growth of the plants. The polyacrylamide gel is non-phytotoxic, slowly biodegradable and has a shelf life of about three years.

In his earlier patent (BF.2552.620), the Applicant has already described a method of producing sod in patches or carpets using a plastic film deposited on the ground on a cane bagasse culture support. sugar mixed with generator ash from the sugar factory in a proportion ranging from 30 to 50%.

It is further provided that the natural decomposition of bagasse is increased by the use of a chemical product of the ACTILEX ® type known to gardeners and possibly a correction of the pH value which tends towards acidification, by limestone lime.

The process according to the invention is a clear improvement and simplification of the previously described process by using more efficient delignification agents and thus ensuring faster and more important seed germination and seedling growth.

Under such conditions decomposition bagasse is substantially accelerated while eliminating or reducing the need for water intake in significant proportions.

Indeed, sugarcane bagasse is a very light vegetable fiber. Its water retention capacity is limited. The nutrient supply results from the degradation of the polysaccharides of the cell membrane.

The addition to the culture medium of ammonia resulting from the progressive hydrolysis of urea contributes greatly to the synthesis of nutrients. In addition, the incorporation of water-retaining grains constitutes an important moistening factor which plays a significant role in the growth of seedlings without the need to provide fertilizers or without the need for irrigation.

The grass mat is obtained by sowing or incorporating turf rhizomes into the vegetable carrier.

The support is deposited on the ground either manually or mechanically. It represents a thickness ranging from 4 to 8 cm. The sod seeds are deposited by means of a pneumatic or mechanical seed drill in a proportion ranging from 10 to 100 grams per square meter depending on the varieties of turf chosen.

When turf rhizomes are used, they are manually or mechanically stitched in the plant support at a rate of 50 to 100 cuttings per m2.

The incorporation of urea into said support is carried out by spraying or dispersing an aqueous solution of urea on the support. The urea solution is at a concentration of from 0.2 to 20% and preferably from 0.5 to 10%. It is distributed at a rate of 2 to 20m1 per m2 of ground support and preferably 4 to 8ml per m2 of support. The addition of the water-retaining product is carried out in a similar manner by dispersing the polyacrylamide polymer grains in the milled vegetable carrier after impregnation with the urea solution.

The sodium salt polyacrylamide polymer is preferably that marketed under the name polyacrylamide sodium salt and sold under the name "grains of water".

It is used in an amount ranging from 0.1 to 5% per m2 of vegetable carpet and preferably from 1 to 2%. The lifetime of this polymer is of the order of 3 years so that its remanence is considerable. The product obtained by the present method allows the cutting of the turf sheet by squares or rectangles of determined dimensions, strips or rolls. These are placed on the ground either of a garden, a roadside, or on any bare surface 45 resulting from a new construction.

Plates, strips or rolls of grass are placed on the ground, ensuring a good jointing of these so as to obtain a homogeneous surface whose growth will be regular and undisturbed. Mowing the turf may take place 8 to 10 days after implantation.

The culture of such a support may also be performed above ground on a plastic film of polyvinyl chloride having 50 to 100 microns thick. Thus, patches of grass are easily detached from the support and can be applied on a ground or on an already leveled and compacted soil, without stopping germination or growth.

The process according to the intervention finds multiple uses for sodding gardens, public spaces, road soils to achieve a rapid coating with turf and avoid erosion, runoff, or gullying phenomena during bad weather as it is common on virgin soils.

Claims (10)

REVENDICATIONS1. Process for the production of a carpet, plates or rolls of turf characterized in that a culture medium consisting of pre-ground sugarcane bagasse is prepared in which seeds or turf rhizomes are incorporated, a source of nitrogen and super absorbent polymer grains water retentive, non-phyto-toxic and weakly biodegradable. 2. Method according to claim 1 wherein the culture support is deposited on a plastic film. 3. The method of claim 1 wherein the nitrogen source is a source of ammonia. 4. The method of claim 1 wherein the source of ammonia is produced by urea whose progressive degradation leads to the formation of ammonia. 5. Method according to claim 1 wherein the urea is incorporated by watering or dispersion of an aqueous solution on the plant support. 6. The method of claim 5 wherein the aqueous solution of urea is at a concentration of 0.2 to 20%, and preferably 0.5 to 10%. 7. Method according to one of the preceding claims wherein the urea solution is spread at a rate of 2 to 20 ml per m2 of plant support. The process according to claim 1 wherein the addition of the water-retaining product is effected by dispersing the polyacrylamide polymer grains in the plant carrier after impregnation with the urea solution. 9. Method according to one of the preceding claims wherein the dispersion of product retentive water at a concentration ranging from 0.1 to 5% per m2 of plant carpet. 10. Use of the grass carpet obtained by the method of claim 1 for the maintenance of the soil of gardens, road borders, public areas, or bare land after new construction.