The division of Bioresources and Health Product Engineering(DBHPE) is composed of six research groups. For exploring biological resources and the development of health products, DBHPE focuses on four key scientific issues: the relationship between biomass structure and biotransformation, principles of high -solid multiphase biological processes, microbial metabolic pathway design and synthetic biology, natural product extraction and functional identification. The DBHPE committed to the integration of multidisciplinary technologies such as biology, chemistry, chemical engineering, and conduct research on enzyme engineering and microbial engineering, bioprocesses, bioengineering and integrated equipment, in order to break through key technologies such as biomass refining, efficient, clean and controllable solid-state fermentation, biosynthesis of high value-added biological products and activity identification of natural active ingredients. DBHPE will provide basic theory and industrialization technical support for biological resource utilization, ecological environment protection and health product development. In 2020, the breakthroughs of this division are as following:
Reduction of enzyme dosage by Fenton reagent for high solids enzymatic hydrolysis of steam-exploded corn stover
The large cellulase dosage is the main factor causing the high cost of lignocellulosic ethanol production, which has become an economic problem. Non-sugar-producing oxidation has been proved to be one of the important processes in the degradation of lignocellulose. The addition of monooxygenase to cellulase preparations has achieved excellent results, but the price of monooxygenase is very expensive, which is not conducive to reducing the cost of cellulase. However, the combination of cheap chemical oxidants and cellulase is expected to achieve the goal of reducing the cost of enzymes. In this study, Fenton’s reagent was used to enhance the high-solid enzymatic hydrolysis process of steam-exploded corn stover. The results show that pre-enzymatic hydrolysis with Fenton’s reagent can effectively promote the high-solid enzymatic hydrolysis process of steam-exploded corn stover. Furtherly, the influences of components of Fenton's reagent, pre-enzymatic hydrolysis temperature and other main factor were on the promotion efficiency of enzymatic hydrolysis was investigated. The analysis of T2 relaxion time showed that the peaks of pool 1 and pool 2 migrated to the right after the pre-enzymatically hydrolysis by Fenton's reagent. The specific surface area analysis showed that after pre-enzymatic hydrolysis with Fenton's reagent, the specific surface area was greatly increased, and the maximum could be increased by 51.09%. Under the condition of 22% solid loading, high-efficiency enzymatic hydrolysis was completed with Fenton's reagent pre-enzymatic hydrolysis with 5 FPU/g, which is 76.19% less than the blank group. According to the economic modeling of lignocellulosic ethanol process, it was found that the use of Fenton’s reagent pre-enzymatic hydrolysis method can reduce the cost of raw materials by 51.8% and reduce the cost of ethanol production per ton by 26.72% reduction, which proved to be an economically advantageous means.
Fig. 1 Fenton reagent reduces the cost of ethanol production
Construction of a strain for efficient synthesis of biodegradable polyhydroxyalkanoates
The production of polyhydroxyalkanoates (PHA), a kind of degradable plastics, from CO2 instead of sugar based raw materials can reduce greenhouse gas emissions and protect environment, which has attracted much attention. Cupriavidus necator can synthesize PHA using CO2, H2 and O2 as substrates. In order to realize safe fermentation, oxygen content in the mixture must be reduced. Based on the study of the metabolic mechanism of PHA synthesis by C. necator under hypoxia, our team improved the respiratory metabolism efficiency by combining the hydrogenase signal peptide gene with the hemoglobin gene VHb, and knocking out the key genes ldh, ackA2, iclA and iclB which contribute for the synthesis of the byproducts of lactate, acetic acid and acetaldehyde. The strain can efficiently produce PHA from CO2 under oxygen limiting conditions.
Fig. 2 Construction of the strain for synthesis of polyhydroxyalkanoates from carbon dioxide
Research and application of key technology for health products from characteristic psammophytes
Based on the idea of promoting ecological management, taking the characteristic plant resources (Cistanche deserticola, Lycium ruthenicum, Cynomorium songaricum, Agriophyllum squarrosum) in the arid desert area of Alashan as the research object, we analysed the nutrition and characteristic active components, and investigated mass transfer law in extraction and separation process in order to solve the problem of high sugar content, long drying time, easily damaged active substances and low resource utilization, and the following technologies were developed:
Ultra high pressure and low temperature jet extraction technology has been developed, which improved the extraction rate and reduced the extraction cost.
High efficiency vacuum concentration technology has been developed, which solved the problem of wall sticking in traditional concentration.
Vacuum pulsating ultrasonic drying technology has been developed, which avoided long drying time and serious browning.
In addition to the development of relevant equipment, the industrialization production process of bioactive ingredients was also established. Six kinds of desert plant health products and the product quality control system have been developed. This research promoted the employment of farmers and herdsmen and realized the sustainable development of arid desert areas.
Fig. 3 Functional components production line for Cistanche deserticola (raw material treatment ≥ 30tons/year)