Progress in biological utilization of formic acid / 生物工程学报

The use of microbial cell factories to achieve efficient conversion of raw materials and synthesis of target substances is one of the important research directions of synthetic biology. Traditional industrial microorganisms have mainly used sugar-based raw materials as fermentation substrates. How to adopt cheaper carbon resources and realize their efficient use has been widely concerned. Formic acid is an important organic one-carbon source and widely used in industrial manufacturing of pesticides, leather, dyes, medicine and rubber. In recent years, due to the demand fluctuation in downstream industries, formic acid production is facing the dilemma of overcapacity, and therefore, requiring new conversion paths for expansion and extension of the related industrial chain. Biological route is one of the important options. However, natural formate-utilizing microorganisms generally grow slowly when metabolizing formic acid, and moreover, are difficult to be artificially modified by the absence of effective genetic tools. Construction of non-natural formate-utilizing microorganisms is another alternative strategy, but still in its infancy and has a huge space for further improvements. Here, we briefly summarize the recent research progress of biological utilization of formic acid, and also propose the future research focus and direction.

INTESTINAL MUCOSAL IRON LEVELS AND ITS UTILIZATION IN INTERMITTENTLY Fe SUPPLEMENTED RATS / 营养学报

Thirty two male weanling Sprague Dawley rats were made iron-deficient or normal-iron by feeding AIN-76 Specifications without or with 0.8mg Fe (divided twice daily). After 12 days both groups of rats were subdivided into two groups, each one received 8mg Fe at intervals of 3 days or daily respectively for 18 days, 3.7?104Bq of 69Fe were added to the first supplemented dose. Measurements included every segment intestinal mucosal Fe and the remaining Fe in washes in intestine, and thier cpm of 58Fe at sacrifice. 59Fe utilization were counted. The results showed that Fe content of intestinal mucosa and washes in daily Fe supplemented rats were from 8 to 20 times that of iron normal control group and 59Fe utilization was doubled. Intestinal mucosal Fe levels were close to that of iron-normal rats. Remaining Fc content in washes was 1/5 of daily Fe supplemented rats. So intermittent Fe supplementation was more efficient and the dose was small and side effect was less than daily supplementation and diminished intestinal Fe loading.