The environmental problems caused by plastics of fossil origin are well known. To reduce harmful impact on the environment, bacterial-based plastics, such as polyhydroxyalkanoates (PHAs), are a promising solution. Mic...The environmental problems caused by plastics of fossil origin are well known. To reduce harmful impact on the environment, bacterial-based plastics, such as polyhydroxyalkanoates (PHAs), are a promising solution. Microbial PHAs can be produced using abundant and inexpensive agricultural by-products as raw material. In this study, the potential use of Cupriavidus necator 11599 for the bioconversion of cassava starch into biodegradable PHAs was explored. Although Cupriavidus necator 11599 is a well-known PHA producer, it cannot grow directly on starch. Thus, acid hydrolysis was carried out on the starch extracted from cassava peels to obtain fermentable sugars. Optimal concentration of reducing sugars (RSs) was obtained by hydrolysis of cassava peel starch with sulfuric acid concentrations of 0.4 N and 0.6 N, at 95˚C and 4 h. The hydrolyzed starch was used for PHA production in Erlenmeyer flasks using reducing sugars (RSs) concentrations ranging from 10 g/L to 25 g/L. The best RS concentration 20 g/L and 25 g/L gave 85.13% ± 1.17% and 89.01% ± 2.49% of biomass PHA content and biomass concentrations of 8.18 g/L and 8.32 g/L, respectively in 48 hours. This research demonstrates that cassava peel starch as an inexpensive feedstock could be used for PHA production, paving the way for the use of other starchy materials to make bioplastics.展开更多
Waste water treatment in order to preserve water resources is one of the major concerns in developing countries. This study aims to test the operating effectiveness of a pilot designed on a basis of several laboratory...Waste water treatment in order to preserve water resources is one of the major concerns in developing countries. This study aims to test the operating effectiveness of a pilot designed on a basis of several laboratory experiments, which consists of an anaerobic and aerobic pond in series. The test was performed through monitoring global parameters of pollution. The results of the analysis of these parameters indicate an elimination of 91% of suspended solids, 68% of COD, 77% of BOD5, 61% of nitrate and 81% of phosphorus. It was also noticed that the anaerobic pond removes most, carbonaceous organic materials and especially suspended matters;and the aerobic pond most, nitrogen and especially phosphorus. This study reveals the effectiveness of the series connection of an anaerobic and aerobic pond for domestic wastewater treatment.展开更多
文摘The environmental problems caused by plastics of fossil origin are well known. To reduce harmful impact on the environment, bacterial-based plastics, such as polyhydroxyalkanoates (PHAs), are a promising solution. Microbial PHAs can be produced using abundant and inexpensive agricultural by-products as raw material. In this study, the potential use of Cupriavidus necator 11599 for the bioconversion of cassava starch into biodegradable PHAs was explored. Although Cupriavidus necator 11599 is a well-known PHA producer, it cannot grow directly on starch. Thus, acid hydrolysis was carried out on the starch extracted from cassava peels to obtain fermentable sugars. Optimal concentration of reducing sugars (RSs) was obtained by hydrolysis of cassava peel starch with sulfuric acid concentrations of 0.4 N and 0.6 N, at 95˚C and 4 h. The hydrolyzed starch was used for PHA production in Erlenmeyer flasks using reducing sugars (RSs) concentrations ranging from 10 g/L to 25 g/L. The best RS concentration 20 g/L and 25 g/L gave 85.13% ± 1.17% and 89.01% ± 2.49% of biomass PHA content and biomass concentrations of 8.18 g/L and 8.32 g/L, respectively in 48 hours. This research demonstrates that cassava peel starch as an inexpensive feedstock could be used for PHA production, paving the way for the use of other starchy materials to make bioplastics.
文摘Waste water treatment in order to preserve water resources is one of the major concerns in developing countries. This study aims to test the operating effectiveness of a pilot designed on a basis of several laboratory experiments, which consists of an anaerobic and aerobic pond in series. The test was performed through monitoring global parameters of pollution. The results of the analysis of these parameters indicate an elimination of 91% of suspended solids, 68% of COD, 77% of BOD5, 61% of nitrate and 81% of phosphorus. It was also noticed that the anaerobic pond removes most, carbonaceous organic materials and especially suspended matters;and the aerobic pond most, nitrogen and especially phosphorus. This study reveals the effectiveness of the series connection of an anaerobic and aerobic pond for domestic wastewater treatment.
