Team:BUCT-China/Description
Description
Engineering
Microbulbifer hydrolyticus
for plastic
degradation and value-added products
Abstract
Plastics are widely used in industry and households because of their low-weight, durability and low-production cost. Nowadays, the consumption of plastics has risen sharply. However, the lack of effective waste plastics management poses a major threat to the environment. For the past few years, new technology about biodegradation of plastics has been a hot spot. Polyethylene (PE) and polystyrene (PS) are the most important mass-produced plastics, which are difficult to be degraded by the microorganism. Recently, we observed a strain Microbulbifer hydrolyticus , which has the ability to degrade PE and PS. In this study, we would try to investigate the mechanism of PE biodegradation, and find the key enzymes. Meanwhile, based on the genome sequencing and synthetic biology, we aim to construct an artificial metabolic pathway, engineering this strain to enhance the ability to plastics biodegrading. Furthermore, the strain could utilize plastics to synthetic value-added products, such as PHA, etc.
Inspiration
Environmental issues cannot be ignored, so many topics on plastic degradation are being studied. In our surroundings, we could see many plastic garbage, and some abandoned plastic garbage seems to have been degraded by nature.In fact a large part of which becomes micro-plastics in ocean and land,then entering the animal’s body through the food chain even our human beings. Because those tiny plastic is really difficult to be collected，so there is currently no good way to deal with these micro-plastic whether using chemical or physical methods,and it has become an urgent part of the problem of plastic pollution. Besides,though many plastics can be degraded and recycled, but it is estimated that roughly 50% plastic will be buried in the land rather deal with them. So it has a large space to improve them in this area. Such as PE can also be degraded into CO2 but its hard to be reused.So recycle is indeed a big problem. Based on the above two issues:collect and recycle, we try to use microbes to find more effective methods. So we are trying to do something on PE in order to contribute a little to our environment, which have profound realistic meaning.
Advantage and disadvantage of plastics
Plastics are widely used in industrial and household applications because of their low weight, durability and low production cost (Andradeeey, 2015). The widespread use of plastics, the lack of waste management and casual social behavior render the production rate is much faster than the degradation rate which poses a major threat to the environment (Leja and Lewandowicz, 2010).
Plastics are hardly to be degraded
Most commonly used plastics are synthetic polymers obtained from petrochemical hydrocarbons and derivatives (Geyer et al., 2017). Polyethylene (PE) and polystyrene (PS) are amongst the most important mass-produced plastics and largely manufactured into short-life products including packaging materials for food and disposable dishware (2018). PE and PS are very stable polymers and notably resistant to biodegradation (Ho et al., 2017).
The recycling of plastic is a bigger problem
Actually almost all the plastic could be degraded by some method but how to recycle and reuse them is a serious problem, it is estimated that roughly 50% plastic will be buried in the land rather deal with them so it has a large space to improve them in this area.
Biodegradation is the future
Shimpi et al. reported the biodegradation of
modified
PS
by
using
a pure
strain of
Pseudomonas
aeruginosa
(Shimpi
et al.,
2012).
Motta
et al.
used
the
Curvularia
species
to
investigate
the
degradation
of
atactic
PS.
These
results
suggested
that
the
biodegradation
of PS
material
through
using
selected
microbial
strains
might
become a
feasible
solution
for
reducing
the
huge
amount
of
waste
and
disposed
plastics
(Motta
et
al.,
2009).
What we can do
In our lab we also observed a strain
Microbulbifer
hydrolyticus
is
able
to
degrade
PE.
The
strain
was
already
sequenced.
Based
on
the
genome
sequence
and
synthetic
biology, we
aim
to
construct
artificial
metabolic
pathway,
engineering
this
strain
in
order
to
enhance
the
ability
for
degrading
plastics;
furthermore,
the
strain could
utilize
plastics
to
synthesis
value-added
products,
such
as
PHA,
etc..
References
[1]Andrady, A. L. (2015). Plastic Products: Plastics and Environmental Sustainability.Hoboken, NJ: John Wiley & Sons, 83–119. doi: 10.1002/9781119009405.ch4
[2]Leja, K., and Lewandowicz, G. (2010). Polymer biodegradation and biodegradablepolymers - a review. Pol. J. Environ. Stud. 19, 255–266.
[3]Geyer, R., Jambeck, J. R., and Law, K. L. (2017). Production, use, and fate of allplastics ever made. Sci. Adv. 3:e1700782. doi: 10.1126/sciadv.1700782
[4]Ho, B. T., Roberts, T. K., and Lucas, S. (2017). An overview on biodegradationof polystyrene and modified polystyrene: the microbial approach. Crit. Rev.Biotechnol. 38, 1–13. doi: 10.1080/07388551.2017.1355293
[5]Plastics Europe (2018). Plastics – the Facts 2018. Available at: www.plasticseurope.org retrieved in 2018.
[6]Shimpi, N., Mishra, S., and Kadam, M. (2012). Biodegradation of polystyrene(PS)-poly(lactic acid) (PLA) nanocomposites using Pseudomonas aeruginosa.Macromol. Res. 20, 181–187. doi: 10.1007/s13233-012-0026- 1
[7]Motta, O., Proto, A., De, C. F., De, C. F., Santoro, E., Brunetti, L., et al. (2009).Utilization of chemically oxidized polystyrene as co-substrate by filamentousfungi. Int. J. Hyg. Environ. Health 212, 61–66. doi: 10.1016/j.ijheh.2007.09.014