Mathematics is mostly related to human life, thus, humans are required to have the mathematical understanding ability in solving life problems since in the elementary school age. Therefore, mathematics learning at school should have relevance value to construct mathematical concept that can be used in real life.  Innovative mathematics learning through Contextual Learning (CTL) model based on Sundanese Culture Ethnomathematics as a local wisdom at which humans use mathematics in their real life, was chosen as a deep solution to increase the mathematical understanding ability, because students live in their culture and society. This study employsan experimental method by conducting pretest and postest control group design. The purpose of this study is to determine the increasing of students’ mathematical understanding ability on experiment class (using CTL model based on Sundanese Ethnomathematics) and control class (using conventional learning model). The result of this study produced conclusion that CTL based on Sundanese ethnomahtematics and conventional model can increasethe mathematical understanding ability significantly. However, the application of CTL model based on Sundanese Ethnomathematics was significantly better than conventional model (62.29%) to increase students’ mathematical understanding ability on learning the basic concepts of rectangular geometry for 4th grade students of elementary school.

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Global consumption of polyethylene terephthalate (PET) increases each year, resulting in considerable buildup of plastic waste in the environment. A whole cell biocatalyst (WBC) with LC-cutinase bound to its outer membrane had been constructed to hydrolyze PET (optimum temperature 55°C). The aim of this study was to improve WBC viability at 55°C by inserting Ef-TU gene from sugarcane into WCB cells, with the hope of improving its hydrolytic activity. Escherichia coli BL21(DE3) was co-transformed with two plasmids, the first contained Lpp-OmpA-LC-cutinase fused gene and the second contained Ef-TU gene. Cells transformed with only the first plasmid were used as control. The cells were grown at 37°C and 55°C and viability was analyzed by total plate count. LC-cutinase activity was measured using pNPB as substrate and its capability to hydrolyze PET was observed by scanning electron microscopy. The presence of Ef-TU improved WCB viability at 55°C after 90 minutes incubation and LC-cutinase activity remained stable after 72 hours incubation at 55°C. LC-cutinase activity of WCB with Ef-TU was consistently higher than without EF-TU. Scanning electron micrograph of PET sheets incubated with WBC cultures with Ef-TU showed larger pockets than without EF-TU.

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