No abstract

A strain NQ1, which showed efficient asymmetric reduction of 3,5‐bis(trifluoromethyl) acetophenone (BTAP) to enantiopure (S)‐[3,5‐bis(trifluoromethyl)phenyl]ethanol ((S)‐BTPE), which is the key intermediate for the synthesis of a receptor antagonist and antidepressant, was isolated from a soil sample. Based on its morphological and internal transcribed spacer sequence, the strain NQ1 was identified to be Rhodotorula mucilaginosa NQ1. Some key reaction parameters involved in the bioreduction catalyzed by whole cells of R. mucilaginosa NQ1 were subsequently optimized, and the optimized conditions for the synthesis of (S)‐BTPE were determined to be as follows: 5·0 ml phosphate buffer (200 mmol l−1, pH 7·0), 80 mmol l−1 of BTAP, 250 g (wet weight) l−1 of resting cell, 35 g l−1 of glucose and a reaction for 18 h at 30°C and 180 rev min−1. The strain NQ1 exhibited a best yield of 99% and an excellent enantiomeric excess of 99% for the preparation of (S)‐BTPE under the above optimal conditions, and could also asymmetrically reduce a variety of bulky prochiral carbonyl compounds to their corresponding optical hydroxyl compound with excellent enantioselectivity. These results indicated that R. mucilaginosa NQ1 had a good capacity to reduce BTAP to its corresponding (S)‐BTPE, and might be a new potential biocatalyst for the production of valuable chiral hydroxyl compounds in industry.

Industrial competition has been extended from the traditional price and quality competition to warranty competition, from the single manufacturer competition to the whole supply chain system competition. Existing research mainly focuses on the decision-making problems of warranty period and price. However, with the increasing complexity and safety requirements of CNC machine tools and other engineering equipment, customers have put forward higher requirements for product quality and equipment reliability. In this paper, the equipment product deteriorating with aging is taken as the research object, and a two-level service supply chain profit model under Stackelberg game with strong manufacturer bundled sales of “product + warranty” is constructed. Moreover, the impact of warranty period and preventive maintenance frequency on the equilibrium price of product-service package is discussed. This paper provides a new and scientific approach for the optimization of product service strategy.