As a catalyst for whole bacteria, the new engineering strains promote the industrialization process of bio-transformation of henycal cellulose.

How to realize the high-value utilization of low-value raw materials such as biomass cellulose has always been a hot research topic at home and abroad.
The metabolomics team of Qingdao Institute of Bioenembed energy and process of the Chinese Academy of Sciences aims to break the foreign technology monopoly and break through the bottleneck of ligand cellulose glycation technology, and has long been committed to the genetic transformation and metabolic engineering of cellulose degradation bacteria such as Clostridium difficion, using a series of genetic operating tools developed by the team (J Microbiol Methods, 2012, 89:201-8.); PloS One 2013, 8:e69032; Appl Microbiol Biotechnol, 2014, 98:313-23; Biotechnol Biofuels, 2015, 8:36.), through the directional transformation of Clostridium difficuls and its cellulose degradation enzyme line, the fibrosis, a new type of engineering strain has been constructed, which can be used as a catalyst for the efficient transformation of ligand cellulose substrates to fermentable sugars, which has greatly promoted the industrialization process of bio-transformation of lithyl cellulose.
The results were published online May 12 in Biotechnology for Biofuels (Zhang J, et al, 2017, 10 (1): 124), with Ph.D. student Zhang Jie as the first author of the paper, researcher Cui Ball and associate researcher Liu Yajun as the author of the paper.
ligand cellulose-based biomass has attracted much attention for its reserves and renewables, but the unreasonable disposal of agricultural and for forest waste will greatly increase environmental pressure and cause serious environmental pollution problems, including water pollution and incineration haze.
therefore, the efficient use of non-food and wood cellulose is a global problem that needs to be solved urgently, and it is of strategic importance to achieve sustainable economic development.
However, the industrialization, scale and commercialization of biomass of wood cellulose has not really been carried out, mainly because it has not yet broken through the bottleneck of high-efficiency, low-cost conversion of wood cellulose into fermentable sugar.
fiber microsomes are one of the most efficient cellulose degradation molecular machines known in nature, as a typical fiber-producing microsome strain, Clostridium Difficulum has the properties of naturally highly effectively degraded cellulose substrates, so it is considered to be the most promising strain that can achieve efficient biocetaxed conversion of ligand cellulose-based by integrating bioprocessing techniques.
however, the existing wild strains and their fibrous bodies have deficiencies such as the feedback inhibition of the hydrolyzed vitality of the substrate and the enzyme catalytic products, and cannot adapt to the requirements of industrialization.
In response to this current state of study, the metabolomics team made targeted modifications to Clostridium difficules and their fibrous bodies, and by establishing a scar-free genome editing system, the beta-glucoside enzyme CabglA, derived from extreme heat-eating bacteria, was fused with the key fibrosis enzyme Cell48S and assembled on the extracellulose microseome (Figure 1).
the recombinant strain was used as a catalyst for glycation and found that when 100 g/L microcrystalline cellulose was used as the substrate, the reduced sugar yield reached 489 mM (converted to approximately 88 g/L in glucose molecular weight) (Figure 2).
the ability of the bacteria to efficiently degrade cellulose and produce fermentable sugars has proved the feasibility of the full-bacteria catalytic glycation strategy of lysine cellulose in industrial applications.
this study expands the new horizon of glycation of wood cellulose, and strongly promotes the replacement of cellulose as a carbon source to starch sugar in the field of industrial fermentation.
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