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Protection of bamboo by environment-friendly chemicals against short-term molding

The World Bamboo Congress VIII. Protection of bamboo by environment-friendly chemicals against short-term molding. TangThi Kim Hong 1,2 , Olaf Schmidt 1 ,Walter Liese 1 1 Center of Wood Science, University of Hamburg, Germany 2 Nong Lam University of Ho Chi Minh City, Vietnam.

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Protection of bamboo by environment-friendly chemicals against short-term molding

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  1. The World Bamboo Congress VIII Protection of bamboo by environment-friendly chemicals against short-term molding TangThi Kim Hong1,2, Olaf Schmidt1,Walter Liese1 1Center of Wood Science, University of Hamburg, Germany 2 Nong Lam University of Ho Chi Minh City, Vietnam

  2. Molds can grow on the surface and at the cross-ends of culms in a humid atmosphere as they require high relative humidity above 70% Background Especially, exposed bamboo material during storage, processing, transport in container and its final use is affected by molds

  3. Molded fresh culms five days after haversting Molded dried culms during storage Molded dried culms during processing Surface of a table exposed by molds Fig. 1a Moulded bamboo culms and materials at a Bamboo factory, Vietnam

  4. Fig 1b. Molded bamboo culms at arrival in Hamburg after container transport from Vietnam

  5. Background For protection of wood and bamboo against molds and other fungi, pentachlorophenol had been widely used Pentachlorophenol is banneddue to its high toxicity in many parts of the world as well as in Vietnam Bamboo manufacturers have pressing problems to protect bamboo for home use and export Manufacturers greatly need cost-effective but also environment-friendly treatment methods

  6. for bamboo short-term protection against molding + the preventing effect of organic acids (applied for food and as antiseptica) the additional protective effect of their low pH-value against microorganisms Objective

  7. Bamboo Specimens Bamboo species Bambusa stenostachya Hackel and Thyrostachys siamensis Gamble (two of the important species of Vietnam) were selected for testing Material and Methods Samples preparation From the fresh culms with MC 100 to 120%, samples of 70 mm length were taken halfway between the internodes and longwise split.

  8. Chemicals

  9. Fungi • The molds used were isolated from bamboo at the Nong Lam University of Ho chi Minh City, Vietnam. • Traditional identification and DNA-ITS sequencing revealed: Aspergillus niger, A. flavus, A. oryzae, Aspergillus sp.,Paecilomyces variotii and Penicillium sp.

  10. Treatment Two specimens of the two bamboo species were dipped 5 min. in the respective treatment solution and placed in a small plastic basin Fig. 2 Specimens in plastic basins for mold protection test

  11. Incubationand Inoculation Test series 1:artificial infection with a water-based mixture of conidia of the molds was performed with a small brush (`artificial infection´) Test series 2: contained the molds from the natural flora of the bamboo plants and from the sample processing (`natural mold flora´)

  12. Assessment of Mold Growth

  13. Results

  14. Fig. 3 View on the artificially infected and differently treated bamboo specimens after 8 weeks of incubation

  15. Results • The effective formulations 10% acetic acid 7%propionic acid prevented mold growth The treatments with totally over the whole incubation period of 8 weeks 10%propionic acid the mixture of 3% boric acid + 7% propionic acid .

  16. Results • The ineffective formulations • all other treatments allowed • severe (rating 3) or very severe (rating 4) mold growth after the first week and • very severely overgrown after the two weeks.

  17. formulation pH value efficacy of anti-mold 2.8 2.9 2.8 10% acetic acid 7% propionic acid 10% propionic acid effective 10% Na-acetate 7% Na-propionate 10% Na-propionate 8.5 8.0 8.5 ineffective Results • aicd pH value,alkaline pH value

  18. Further results • No significant differences in final molding (after 8 weeks) between the test series `artificial infection´ and `natural mold flora´ • Both bamboo species behaved rather similar regarding mold susceptibility and prevention

  19. Conclusions • The laboratory experiments have shown that molding of bamboo can be prevented by simple treatment with environment-friendly chemicals • Treatment of bamboo samples with acetic acid, propionic acid and a mixture with boric acid prevented mold growth for 8 weeks • The other chemicals were less effective or ineffective • The protection was related to the pH value of the treatment solution. The acetic and propionic acid had protective effect, their salts did not

  20. Recommendations • Experiments with the effective formulations will be continued under field conditions in Vietnam with larger bamboo dimensions as culms, round and split, as well as handicrafts and commodities • Since molding of bamboo is a serious devaluation in trade, corresponding experiments are recommended for other bamboo countries with their respective species

  21. Acknowledgments Bamboo Nature LTD. Company, Vietnam

  22. Thank you for your attention!

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