Currently research is being carried out in 2 main areas; Biofuel and soil C sequestration with sub projects in each category. A fair amount of studies have been reported and some data are available on the above ground C-sequestrations of the major vegetational types of Sri Lanka. However, very little or no information is available on the below ground or soil C sequestration. In consideration of the importance as well as the long term stability of soil stored C it is essential to fill this gap of knowledge on soil C-sequestration in Sri Lanka with respect to the country’s carbon budget. Therefore in this project soil C sequestration potential and its dynamics will be studied in the different major vegetation types of Sri Lanka. Major vegetations of Sri Lanka include natural and plantation forests, agricultural plantations, farm lands and small holder cultivations, wetland paddies, dry and wet grasslands or patanas, mangroves etc. The biofuel project aims to explore the microbial flora of Sri Lanka to isolate efficient degraders of cellulose, hemicellulose and lignin, study the effect of biofilms and/or co-cultures on degradation of cellulosic biomass. Lignocellulosic materials from plants are a rich source of sugars. However,current production processes are economically unviable partly due to the costs of pre-treatment andhydrolytic ezymes. The present project aims to study possible enhancement of enzyme production by formation of co-cultures or biofilm formation. In addition, the possibilty of overcoming nitrogen limitation during enzyme production by co-culturing cellulolytic fungi with nitrogen fixing bacteria is being studied. For the purpose of biological pre-treatment, a number of basidiomycetes have been grown in vitro and screened for ligninolytic enzymes and their potential for degrading lignin is being explored. Organic component of algae could also be used as raw material for biofuel production. Algae are rich in poly unsaturated fatty acids hence; enhance the potential as a source for biofuel. This research will examine the possibilities of using cyanobacteria and algal species available in fresh water bodies of Sri Lanka for biofuel production.
Forest soils play an important role as a carbon sink, which means that it can absorb and hold carbon for hundreds to thousands of years without releasing it as CO2 into the atmosphere. This study is based on soil C sequestration in different landuse types of Knuckles Forest Region; where a wide range of climatic conditions and vegetation types are available. Montane forests (MF), Sub Montane forests (SMF), Open and Sparse forests (OSF) and Grasslands (GL) were selected for the study.
Fig. 1. Sampling in Sub Montane Forest
In addition to C sequestration, soil nutrient levels of these landuse types were also estimated. Results showed that TOC content was significantly highest in MF followed by SMF and lower in both OSF and GL. Montane forests also recorded higher MBC, LC and WSC contents (0.14 %, 715.2 mg/kg, 0.46 % respectively) compared to the other studied landuse types. Soil C stocks varied significantly (p<0.05) among these forest types, where MF recorded the highest soil C stock in top soil layer (0-15cm). The results show that MF and SM forests have a greater ability of sequestering C compared to other studied landuse types in the Knuckles forest region.
Paddy represents a large portion of global agriculture and grown largely in South and East Asian countries. Soil organic carbon accumulation in paddy ecosystems was faster and more pronounced than the other arable ecosystems as organic matter decomposition is lessened in lowland rice fields, apparently due to excessively reduced conditions.However no research has been done in Sri Lanka to study soil C stocks in lowland paddy soils. The objective of this study was to assess the total organic carbon and its fractions and nitrogen availability in the paddy soils of Northern Province of Sri Lanka. This study was carried out in Jaffna, Kilinochchi, Vavuniya, Mannar, Mullaitheevu districts of Northern Province of Sri Lanka. There were significant variations in total organic carbon and its fractions, nitrate and ammonium availability among soil great groups of paddy fields of Northern Province of Sri Lanka.TOC content of top soils in ton/ha was highest to the grumusols (54.83 tons/ha) and lowest to the regosols (10.55 tons/ha) in paddy fields of Northern Province.
Biofuels are considered as an important means of reducing greenhouse gas emissions and increase energy security by providing a viable alternative to fossil fuels. Algae biomass is a potential source of 3rd generation biofuel that could surpass all the others due to its rapid growth and extremely high yield potential. Therefore, the aims and goals of the present study are: Morphological identification of cyanobacteria and other algae in fresh water bodies of Sri Lanka as a suitable feed stock for biodiesel production, Optimizing semi-mass culturing of selected cyanobacteria and other algal species, Isolating the other algal products and value added compounds of commercial interest from the residue of algal biomass, Extraction of fatty acids from selected cyanobacteria and other algal species, Molecular characterization of isolated cyanobacteria and other algae, Producing bio diesel from extracted lipids. For the last 12 months a total number of 52uni algal cultures were isolated from 25 fresh water bodies representing three climatic zones of Sri Lanka. The morphological identification of the isolates were also carried out. Isolates were tested for antioxidant, anti-pathogenic activities. The results indicated that cyanobacteria are rich in antioxidants with anti-pathogenic properties.
At the same time, different type of pigments such as phycoerytherin (PE), phycocyanin (PC) & allophycocyanin (APC), Chlorophyll-a (Ch-a), Chlorophyll-b (Ch-b) and Carotene (C x+c) were extracted from selected cyanobacteria which can be used in food and pharmaceutical industry. Also cyanobacteria species were tested for treating waste water and found that there is a potential to use in waste water treatment.
The enzymes involved in degradation of lignocelluloses include cellulases, hemicellulases and lignin degrading enzyme Cellulases can be further categorized as endoglucanases, exoglucanases and β glucosidases. Different microbes produce different proportions of these enzymes. Therefore, co-culture of different microbes may result in a more efficient mixture of enzymes for degradation of enzymes. Also, biofilms of the enzyme producing may have enhanced expression of the enzymes. Among the fungal-fungal co-cultures tested so far, those betweenTrichoderma reesei and Eupenicillium sp have been found to produce more efficient enzyme mixture than their monocultures. Fungal-bacterial co-cultures have been found to be less effective.
Nitrogen level in the medium is another factor that can limit enzyme production. Co-culture of enzyme producing fungi with nitrogen fixing bacteria is being studied to determine whether the bacteria can replenish nitrogen in the medium. Lignin degrading enzymes (laccases, Mn peroxidases, lignin peroxidases etc) are mostly produced by the basidiomycetes group of fungi. So far 42 different basidiomycetes have been isolated and screened for the lignin degrading enzymes. Isolates with high enzyme activities were tested for their ability to degrade lignin in culture medium. Pycnoporus sanguineus was found to degrade alkali lignin in monoculture, while isolate M14 was found to degrade akali lignin in mixed culture with Cellulomonas biazotea.
Pycnoporus sanguineus: Capable of degrading lignin
NRC No. 12-031 Rs 5,945,027.00 (59450$)-National Research Council, Sri Lanka “Biofuel and other microbial products from cellulosic biomass”
Ms. S.K. Jayasekara
Mr. M.D. Fuad Hossain
Mr. A. K. Pathirana