Bioaugmentation of oil and fat degradation in the laboratory
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Abstract
In the current study the ability of commercial microbial supplements to degrade fat and oil under laboratory conditions was assessed. Several of the multi-species commercial inocula investigated were capable of significantly enhancing the degradation of a variety of oils (by ca.15-60%) whilst other multi-species supplements and all of the single strained supplements tested were not.
The principle route by which the commercial inocula degraded fat/oil in the laboratory was ß-oxidation. There was also evidence of mid-chain hydroxylations and oxidations and of hydrogenation on a few occasions but these pathways appeared to be of minor importance relative to ß-oxidation. The microbial supplements generally hydrolysed and degraded the major fatty acids present in the oils (16:0, 18:0, 18: l (i))9, 18: 1(i)7, 18:2(i)6 and 18:3(i)3) at the
same rate, in contrast to environmental isolates which preferentially degraded 18 :3(i)3 and 18:2(i)6 relative to 16:0 and 18:0 often resulting in the formation of particulate material likely to cause problems in drains, sewers and grease traps.
Some of the multi-species microbial formulations were able to grow or degrade oil over a wide range of environmental conditions, adhere to fat and/or plastic surfaces and produce digestive enzymes, indicating that they were equipped to degrade oil under field conditions. None of the supplements were capable of enhancing oil degradation in the presence of the cultured grease trap isolates, however, suggesting that the efficacy of commercial inocula in the field may be mixed.
The identities of the microorganisms involved in the degradation of oil were not fully resolved but it was clear that different groups of bacteria dominated under different environmental conditions. Efficient oil degradation was only observed when the microbial community structure was diverse and changed markedly with time, suggesting that a specific group of microoganisms was responsible for the degradation of the oil or that several microorganisms degraded the oil in a sequential manner.
The principle route by which the commercial inocula degraded fat/oil in the laboratory was ß-oxidation. There was also evidence of mid-chain hydroxylations and oxidations and of hydrogenation on a few occasions but these pathways appeared to be of minor importance relative to ß-oxidation. The microbial supplements generally hydrolysed and degraded the major fatty acids present in the oils (16:0, 18:0, 18: l (i))9, 18: 1(i)7, 18:2(i)6 and 18:3(i)3) at the
same rate, in contrast to environmental isolates which preferentially degraded 18 :3(i)3 and 18:2(i)6 relative to 16:0 and 18:0 often resulting in the formation of particulate material likely to cause problems in drains, sewers and grease traps.
Some of the multi-species microbial formulations were able to grow or degrade oil over a wide range of environmental conditions, adhere to fat and/or plastic surfaces and produce digestive enzymes, indicating that they were equipped to degrade oil under field conditions. None of the supplements were capable of enhancing oil degradation in the presence of the cultured grease trap isolates, however, suggesting that the efficacy of commercial inocula in the field may be mixed.
The identities of the microorganisms involved in the degradation of oil were not fully resolved but it was clear that different groups of bacteria dominated under different environmental conditions. Efficient oil degradation was only observed when the microbial community structure was diverse and changed markedly with time, suggesting that a specific group of microoganisms was responsible for the degradation of the oil or that several microorganisms degraded the oil in a sequential manner.
Details
| Original language | English |
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| Award date | Jan 2003 |