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− | <p> We infer PLA can degrade to lactate that could enter into metabolic cycle of anaerobic bacteria, generating CH4 (methane) and/or CO2[2] . This condition with no oxygen could be found it at typical landfills so in a hypothetical situation where PLA would be established in our society (it means we would use PLA instead of fossil plastic) huge amount of PLA could aggravate the global warming (due to greenhouse gases)[3] . Nevertheless, a controlling degradation of PLA would permit take advantage of CH4 generation to produce energy if it is combusted and would help reduce the effects of climate change[4]. If we implemented our project in long term we would promote cultivation of macroalgae which could contribute to economic development of Chile. Also, macroalgae don’t require arable land, fertilizer or fresh water resources and is a renewable resource , so it is a better alternative than corn cultivation. Nevertheless, a Chilean regulation of macroalgae uses should be constantly checked to avoid overexploitation and imbalance of natural ecosystem where macroalgae live. </p> | + | <p> We infer PLA can be degraded into lactate, which could enter into the metabolic cycle of anaerobic bacteria, generating CH4 (methane) and/or CO2[2] . Environments without oxygen could be found in typical landfills, so in a hypothetical situation where PLA would be established in our society (it means PLA would have totally replaced plastic from fossil origin), huge amounts of PLA could worsen the global warming (due to greenhouse gases emissions)[3] . Nevertheless, a controlled degradation of PLA would allow to take advantage of CH4 generation by producing energy from its combustion and would help to reduce the effects of climate change[4]. If we implemented our project in the long term we would promote cultivation of macroalgae which could contribute to economic development of Chile. Also, macroalgae don’t require any farmland, fertilizer or fresh water and is a renewable resource, so it is a better alternative than corn cultivation (which is one of the main current production modes). Nevertheless, the Chilean regulation of macroalgae uses should be constantly checked to avoid overexploitation and imbalance of natural ecosystem where macroalgae live. </p> |
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− | <p>We think one advantage of using macroalgae it we could make a close-cycle; it means macroalgae would consume environmental CO2 generated in the PLA production process, allowing global reduction of CO2. In the case of fossils plastic this wouldn’t occur due to fossils plastic are made of fossil combustible which positively contribute to global CO2 amount if they are partially degraded or combusted . </p> | + | <p>We think one advantage of using macroalgae is that it could close the carbon cycle; it means macroalgae would consume environmental CO2 generated in the PLA production process, allowing global reduction of CO2. In the case of fossil plastic this wouldn’t occur because current plastics are made of fossil combustible, which positively contributes to increase global CO2 amounts if they are partially degraded or combusted . </p> |
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− | <p> On the other hand, the big problem of fossil plastic is it accumulation[5] . For example, if we suppose a constantly production of the same amount of PLA and PET (a fossil plastic), after 5 years, it would expect find a higher amount of PET than PLA due to a percentage of PLA should be degraded in the first two years[6] . But if PLA had a short degradation time, we guess people maybe would replace it more frequently, so higher amount of PLA product could be thrown away and maybe accumulation rate could be higher than degradation rate. We think this kind of trade off should need further analysis to evaluate the real impact of uses of PLA. | + | <p> On the other hand, the big problem of fossil plastic is its accumulation[5] . For example, if we suppose a constant production of the same amount of PLA and PET (a fossil plastic), after 5 years, higher amounts of PET would b expected to be found because a percentage of PLA should be degraded in the first two years[6] . But if PLA had a short degradation time, we guess people would replace it more frequently by buying more PA products, so higher amounts of PLA could be thrown away and the accumulation rate would increase. We think the trade off between replacing fossil plastics and avoiding an overproduction of PLA should need further analysis to evaluate the real impact of the PLA production process. |
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− | According to functionality of PLA, we recommend it to products which will have a short life-time (<2 years), for example plastic glasses or bags. Contrarily, to products that need a long life-time, for examples piping, big structures, it would be appropriate to remain using fossils plastic. On the particular case of medical use, we think PLA should be used like suture, because sutures need to be degraded in a short time [ref suture].</p> | + | According to the previous reflection, we recommend to use PLA for products which will have a short life-time (<2 years), for example plastic cups or bags. On the contrary, for long life-time products such as pipes, chairs or big structures, it would be appropriate to keep using fossil plastics. On the particular case of medical use, we think PLA should be used like suture, because sutures need to be degraded in a short time [ref suture].</p> |
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