In Southeast Asia, the conversion of native forests to oil palm plantations threatens tropical bi... more In Southeast Asia, the conversion of native forests to oil palm plantations threatens tropical biodiversity, but very little is known about the impacts of oil palm cultivation on small carnivore species. To determine the diversity and occupancy of small carnivores within oil palm plantations and to investigate possible factors that might affect their presence within oil palm, we used camera-traps within two oil palm plantations in central Sumatra, analysed the data using occupancy modelling and tested whether two covariates (distance to the edge of the oil palm habitat and distance from extensive areas of lowland forest) affected the model parameters for each small carnivore species. From 3164 camera-trap days, we detected only three small carnivores: leopard cat (Prionailurus bengalensis), common palm civet (Paradoxurus hermaphroditus) and Malay civet (Viverra tangalunga), which indicates that there was a low diversity of small carnivores within the oil palm plantations. Both the leopard cat and common palm civet were found deep within the oil palm, whereas the Malay civet was only detected near the edge in one of the plantations. The leopard cat and common palm civet had very high occupancy values, whereas the Malay civet had low values for both occupancy and detection probability. Neither covariate affected occupancy of the leopard cat and common palm civet, but distance from the edge of the oil palm habitat did influence their detection probabilities. Malay civet occupancy decreased with distance from the oil palm edge, and detection probability was affected by distance from extensive areas of lowland forest. Forests and rest/den site availability are suggested to be important features for small carnivores with oil palm-dominated landscapes.
For sustainable oil palm production, barn owl (Tyto alba) predation should be enhanced and monito... more For sustainable oil palm production, barn owl (Tyto alba) predation should be enhanced and monitored to better understand its impact on rodent population dynamics, notably for selective predation based on age or size. Our aim was to assess the best combination of osteometric variables that predict eye lens weight and thus the relative age of an individual Rattus tiomanicus based on pellet remains. We captured 161 individuals in an oil palm plantation in Indonesia and measured 15 osteometric variables for the jaw, skull, and femur. We investigated the variables' correlations with eye lens weight and estimated the measurement errors. In addition, 120 pellets were collected to assess the frequency of different types of bones. Predictive modelling was then used. We suggest that the model using the femur length would be more appropriate, even if it is slightly less precise than the models that consider the skull and jaw variables. The femur was well represented in the pellet sample, its length highly correlated with the eye lens weight, with a low measurement error. Our study demonstrates the utility of femur length for age prediction in prey from macroremains in oil palm plantations, wherein most pellets are headless and R. tiomanicus is the dominant prey.
The effectiveness of superheated steam pretreatment on the enzymatic saccharification of oil palm... more The effectiveness of superheated steam pretreatment on the enzymatic saccharification of oil palm mesocarp fiber (OPMF) was investigated by varying the temperature (140 to 210 °C) and the retention time (20 to 90 minutes). The results showed that superheated steam pretreatment at 180 °C for 60 minutes is the optimum condition for enzymatic saccharification of OPMF. Scanning electron microscopy (SEM) images of the OPMF show that superheated steam pretreatment is able to remove silica bodies. Further characterization by FTIR and TG/DTG analysis of the raw and treated OPMF indicates that the solubilization and removal of hemicelluloses took place after the pretreatment. This suggested that superheated steam pretreatment is an effective method for the alteration of the OPMF structure and enhances the digestibility of the biomass, hence improving enzymatic saccharification.
Nanobiocatalysis is a new frontier of emerging nanosized material support in enzyme immobilizatio... more Nanobiocatalysis is a new frontier of emerging nanosized material support in enzyme immobilization application. This paper is about a comprehensive review on cellulose nanofibers (CNF), including their structure, surface modification, chemical coupling for enzyme immobilization, and potential applications. The CNF surface consists of mainly -OH functional group that can be directly interacted weakly with enzyme, and its binding can be improved by surface modification and interaction of chemical coupling that forms a strong and stable covalent immobilization of enzyme. The knowledge of covalent interaction for enzyme immobilization is important to provide more efficient interaction between CNF support and enzyme molecule. Enzyme immobilization onto CNF is having potential for improving enzymatic performance and production yield, as well as contributing toward green technology and sustainable sources.
Changes in the lignocellulosic structure of oil palm empty fruit bunches (OPEFB) during compostin... more Changes in the lignocellulosic structure of oil palm empty fruit bunches (OPEFB) during composting treatment using an in-vessel composter was investigated in this work. The composting process was completed within 40 days of treatment, and the final C/N ratio achieved was 13.85. Scanning electron microscopy (SEM) revealed that the structure of OPEFB material was severely degraded, especially during the thermophilic phase where the biodegradation process was most active. Close examination of the physicochemical and thermal analysis using X-ray diffraction (XRD), Fourier transform infrared (FTIR), and thermogravimetric and differential thermal analysis (TG/DTA) showed that the crystallinity size of the OPEFB structure decreased. This result was attributed to the removal of silica bodies from OPEFB materials. Also, the functional groups of cellulose, hemicelluloses, and lignin structures had changed throughout the composting period, and the most extensive degradation of cellulose was detected in the thermophilic phase. It was also found that the exothermic peak of the matured compost reduced most significantly compared to the raw OPEFB. In conclusion, the in-vessel composting system was able to enhance the degradation process of OPEFB materials for producing compost.
In Southeast Asia, the conversion of native forests to oil palm plantations threatens tropical bi... more In Southeast Asia, the conversion of native forests to oil palm plantations threatens tropical biodiversity, but very little is known about the impacts of oil palm cultivation on small carnivore species. To determine the diversity and occupancy of small carnivores within oil palm plantations and to investigate possible factors that might affect their presence within oil palm, we used camera-traps within two oil palm plantations in central Sumatra, analysed the data using occupancy modelling and tested whether two covariates (distance to the edge of the oil palm habitat and distance from extensive areas of lowland forest) affected the model parameters for each small carnivore species. From 3164 camera-trap days, we detected only three small carnivores: leopard cat (Prionailurus bengalensis), common palm civet (Paradoxurus hermaphroditus) and Malay civet (Viverra tangalunga), which indicates that there was a low diversity of small carnivores within the oil palm plantations. Both the leopard cat and common palm civet were found deep within the oil palm, whereas the Malay civet was only detected near the edge in one of the plantations. The leopard cat and common palm civet had very high occupancy values, whereas the Malay civet had low values for both occupancy and detection probability. Neither covariate affected occupancy of the leopard cat and common palm civet, but distance from the edge of the oil palm habitat did influence their detection probabilities. Malay civet occupancy decreased with distance from the oil palm edge, and detection probability was affected by distance from extensive areas of lowland forest. Forests and rest/den site availability are suggested to be important features for small carnivores with oil palm-dominated landscapes.
For sustainable oil palm production, barn owl (Tyto alba) predation should be enhanced and monito... more For sustainable oil palm production, barn owl (Tyto alba) predation should be enhanced and monitored to better understand its impact on rodent population dynamics, notably for selective predation based on age or size. Our aim was to assess the best combination of osteometric variables that predict eye lens weight and thus the relative age of an individual Rattus tiomanicus based on pellet remains. We captured 161 individuals in an oil palm plantation in Indonesia and measured 15 osteometric variables for the jaw, skull, and femur. We investigated the variables' correlations with eye lens weight and estimated the measurement errors. In addition, 120 pellets were collected to assess the frequency of different types of bones. Predictive modelling was then used. We suggest that the model using the femur length would be more appropriate, even if it is slightly less precise than the models that consider the skull and jaw variables. The femur was well represented in the pellet sample, its length highly correlated with the eye lens weight, with a low measurement error. Our study demonstrates the utility of femur length for age prediction in prey from macroremains in oil palm plantations, wherein most pellets are headless and R. tiomanicus is the dominant prey.
The effectiveness of superheated steam pretreatment on the enzymatic saccharification of oil palm... more The effectiveness of superheated steam pretreatment on the enzymatic saccharification of oil palm mesocarp fiber (OPMF) was investigated by varying the temperature (140 to 210 °C) and the retention time (20 to 90 minutes). The results showed that superheated steam pretreatment at 180 °C for 60 minutes is the optimum condition for enzymatic saccharification of OPMF. Scanning electron microscopy (SEM) images of the OPMF show that superheated steam pretreatment is able to remove silica bodies. Further characterization by FTIR and TG/DTG analysis of the raw and treated OPMF indicates that the solubilization and removal of hemicelluloses took place after the pretreatment. This suggested that superheated steam pretreatment is an effective method for the alteration of the OPMF structure and enhances the digestibility of the biomass, hence improving enzymatic saccharification.
Nanobiocatalysis is a new frontier of emerging nanosized material support in enzyme immobilizatio... more Nanobiocatalysis is a new frontier of emerging nanosized material support in enzyme immobilization application. This paper is about a comprehensive review on cellulose nanofibers (CNF), including their structure, surface modification, chemical coupling for enzyme immobilization, and potential applications. The CNF surface consists of mainly -OH functional group that can be directly interacted weakly with enzyme, and its binding can be improved by surface modification and interaction of chemical coupling that forms a strong and stable covalent immobilization of enzyme. The knowledge of covalent interaction for enzyme immobilization is important to provide more efficient interaction between CNF support and enzyme molecule. Enzyme immobilization onto CNF is having potential for improving enzymatic performance and production yield, as well as contributing toward green technology and sustainable sources.
Changes in the lignocellulosic structure of oil palm empty fruit bunches (OPEFB) during compostin... more Changes in the lignocellulosic structure of oil palm empty fruit bunches (OPEFB) during composting treatment using an in-vessel composter was investigated in this work. The composting process was completed within 40 days of treatment, and the final C/N ratio achieved was 13.85. Scanning electron microscopy (SEM) revealed that the structure of OPEFB material was severely degraded, especially during the thermophilic phase where the biodegradation process was most active. Close examination of the physicochemical and thermal analysis using X-ray diffraction (XRD), Fourier transform infrared (FTIR), and thermogravimetric and differential thermal analysis (TG/DTA) showed that the crystallinity size of the OPEFB structure decreased. This result was attributed to the removal of silica bodies from OPEFB materials. Also, the functional groups of cellulose, hemicelluloses, and lignin structures had changed throughout the composting period, and the most extensive degradation of cellulose was detected in the thermophilic phase. It was also found that the exothermic peak of the matured compost reduced most significantly compared to the raw OPEFB. In conclusion, the in-vessel composting system was able to enhance the degradation process of OPEFB materials for producing compost.
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