Can fungi and related microorganisms induce agarwood formation?

Abstract

Presented at the 20th International Forestry and Environmental Symposium

November 2015

Imalka Hitihamu, Upul Subasinghe, Preeni Fernando

Gyrinops walla Gaertn is the only agarwood forming species naturally growing in Sri Lanka. This species, belongs to the family Thymalaeaceae is commonly growing in the low country wet zone of Sri Lanka where the annual rainfall is high. Being very valuable due to the pleasant aroma, agarwood resin is extensively used in cosmetic manufacturing, cultural and religious activities. It is produced as a result of a self-defense mechanism towards any stress caused by several factors which can be physical, chemical and biological. However, use of fungal species to artificially induce agarwood resin formation in Aquilaria species is common in the Southeast Asian region. The present study aimed to explore the possibility of inducing agarwood formation in G. walla trees using Actinomycetes species.

Actinomycetes species were isolated from fresh agarwood resinous tissues of G. walla and associated soils by culturing them in the laboratory. In order to do that, the Actinomycetes species growing with other fungal species in the culture plates were identified using their colony characteristics, reproductive structures and then pure cultures were prepared. Two g of Actinomycetes with solid agar medium was inoculated into non-agarwood formed G. walla trees under aseptic conditions. Observations were made for the agarwood resins in the stem tissues at 10 cm intervals above and below the inoculated points at monthly intervals. Discolouration of the stem tissues was recorded in the field. Resin contents (w/w%) were determined by solvent extraction and the constituents were analysed using GC-MS technique. Stem tissue discolouration varying from yellow to black was observed form the first month after the inoculation. Resin contents varied from 0.03% to 1.66% and high resin contents were observed in dark coloured tissues usually extracted closer to the inoculation points. Moreover, 12 constituents were identified which were also common to the agarwood resins extracted from the Aquilaria species. This study is the first attempt in Sri Lanka investigating the potential of Actinomycetes species as inducing agents of agarwood formation and results reveal that Actinomycetes species are effective microorganisms in production or agarwood resins in G. walla

Extraction of agarwood resins from Walla patta

Agarwood resin, considered to be the most valuable plant product has been kept as a secret in most of the time by the distillers at homestead and industry levels in southeast Asian countries where the Aquilaria trees are grown. After the discovery of the presence of agarwood resins in Walla patta naturally growing in Sri Lanka, the Forest Management Group of University of Sri Jayewardenepura, headed by Dr. Upul Subasinghe started trials on agarwood resin extractions to support the industry and homestead level distillers that are expected to be formed in near future. 

The trials were conducted using a locally manufactured mini-distillation facility with varying water:agarwood ratio, distillation time and the particle size. The results proven that all the selected parameters above have significant impacts on both the oil content and quality which was tested by using GC-MS and GC-FID methods.

Now those results are being further tested using an imported agarwood distillation facililty of medium-scale from Thailand to identify the best energy type and the resin quality improvement methods.

Financial assistance for this project was rendered by the National Research Council and Sadaharitha Plantations Limited via Public-Private-Partnership Programme.

Walla patta seed germination trials - A success after many attempts

After two unsuccessful attempts, Dr. Upul Subasinghe and his team managed to germinate Walla patta seeds under the nursery conditions. The initial attempts were failed due to the use of poor quality seeds collected from the mother trees and medium used which was not very much supportive for the germination of the seeds. Although still the germination rate is below 10%, the last attempt was considered as successful because these results lead to the next set of trials of germination rate enhancement. The germinated seedlings were transferred to the poly-pots of seedling medium and were kept inside the nursery. With the upcoming rains, those seedlings will be used for plantation established and different planting models will be tested in those trials.

The following pictures show the germination beds and the seedlings raised. 

Taking Walla patta to the international communinty

Dr. Upul Subasinghe and his research team managed to take Walla patta (Gyrinops walla) to the international community through some scientific publications on the research findings. Up to now, two full papers were published in two reputed scientific journals and those can be viewed by the following links.

1. Title: "Agarwood type resin from Gyrinops walla: A new discovery"

http://journals.sjp.ac.lk/index.php/JTFE/article/view/594

2. Title "Agarwood resin production and resin quality of Gyrinops walla"

http://internationalscholarsjournals.org/journal/ijas/articles/agarwood-resin-production-and-resin-quality-of-gyrinops-walla-gaertn

In addition to that Dr. Subasinghe presented a paper on "Agarwood resin production of Gyrinops walla" at the International Scientific Symposium held in the University Putra Malaysia from 4 to 7 September 2013. The abstract of that presentation is given below.

Gyrinops walla, a member of the agarwood family Thymelaeaceae is recorded in the wet zone of Sri Lanka has not been previously studied to identify its ability of producing agarwood. Therefore the present study was the first ever to conduct to identify the production of agarwood resins in G. walla and its resin quality.

Three distinctive areas of the low country wet zone of Sri Lanka were selected for this study and 22 G. walla trees were used for sample collection. Since there were no artificial resin induction methods applied earlier, all selected trees had natural wounds occurred sometime before the sample collection due to natural injuries. The dark coloured tissues of the affected areas were collected without felling the trees and the resins were extracted by a solvent extraction method. The diameter and height of the sampled trees were measured and the geographical positions were also recorded. The extracted resins were further analysed by using gas chromatography technique to identify the different compounds and to compare those compounds with that of selected Aquilaria species.

Dr. Subasinghe presenting his research findings at the Malaysian Symposium

14,000 kg of smuggled Walla patta caught in Sri Lanka worth of US$ 1.6 Million - The value is a lie

In last may, all Sri Lanka media had a hit news in catching 14,000 kg of smuggled Walla patta scientifically known as Gyrinops walla by the Police and the Special Task Force. The price was given as US$ 1.6 million. According to the images showed in the electronic media, those tree samples appeared to be white, which means, there was no or very little agarwood formed in the trees. According to the experiments conducted by Dr. Upul Subasinghe and his team from 2010, about 95% wild-grown Walla patta trees do not produce Agarwood resins. Even if the resin is formed, it is due to natural reasons and therefore it does not evenly spread in the stem.

On the 31st of the same month, China Custom's Department has caught 8.145 kg of Agarwood formed in Aquilaria sinensis trees and the images shown below contain the real "Black Colour" Agarwood. According to the China Custom's sources, those Agarwood pieces are Class II in quality and even not Class I.

Therefore the person or persons valued the smuggled Sri Lankan Walla patta trees as US$ 1,143 per kilo has made another crime by lying to the public and showing the lack of knowledge in the trade. Further, this type of irresponsible behaviour leads to destroy the valuable Walla patta resource in Sri Lanka.

The Agarwood resins have to be artificially formed in the correct size of trees and in the next 6 to 12 month of time, Dr. Upul Subasinghe and his team will be able to come up with the best methods of forming resins in Walla patta under the research grant awarded to them worth about US$ 93,000 by the Government and the Private Sector.

Dr. Upul Subasinghe was awarded SLR 11.6 million to conduct further research on Walla patta

Under the Public-Private-Partnership Programme of the National Research Council (NRC) of Sri Lanka, it has awarded SLR 11.6 million Dr. Upul Subasinghe for conducting further research on Walla patta (Gyrinops walla). Sadaharitha Plantations Limited jointly funds this three year research programme with the NRC.

The Public-Private-Partnership programme is a result of the budget proposals over the past few years to strengthen the economy by scientific and technological findings. Moreover, the present proposal, which was among the 6 selected ones for funding by the NRC over 60 applications, is in line with the Green Economy concept of the Sri Lanka Government.

It is expected to obtain the following information by conducting the proposed research project .
1. The seed germination methods
2. Most effective agarwood resin induction methods
3. Agarwood quantity and quality variations with tree size, age and climatic conditions
4. Optimum resin extraction methods

The findings will definitely contribute to the national economy of Sri Lanka by providing silvicultrual, chemical and technological information that are required for large and medium scale Walla patta plantation development in the country. In addition, the results will benefit the villagers living in the low country wet zone of Sri Lanka by providing the correct information on planting methods, resin formation and harvesting times of this precious tree currently exploited without having a proper knowledge on its value.

Ministry of Economic Development accepted the name Sri Lankan Agar for Walla Patta

Due to the proven high Agarwood resinous value of the Walla patta (Gyrinops walla) trees, Dr. Upul Subasinghe who is a committee member of popularising Walla patta tree cultivation among villagers and other relevant bodies, suggested the name "Sri Lankan Agar" for this species in order to make a Brand Name in the international market. The Ministry accepted the name based on the reasons provided by Dr. Subasinghe and decided to use the name Sri Lankan Agar from now on.

According to the results over three year research, Dr. Subasinghe believes the quality of Sri Lankan Agar matches with the other Agarwood products coming to the international market from the South Asian countries. Therefore the Agarwood production of Walla patta, if properly developed, can be used to earn a significant foreign income contributing to the poverty alleviation of the rural community in the low country wet zone.