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CO 2 -derived methanol is an attractive raw material for biobased production of value-added chemicals. Here, we investigated the native methylotrophButyribacterium methylotrophicum, which could synchronously assimilate methanol and CO 2 to butyric acid anaerobically. Supplementation with an approximate amount of bicarbonate could improve methanol metabolism of B. methylotrophicum, and 2.04 g/L butyric acid was finally obtained from 100 mM methanol and 20 mM bicarbonate. The genes involved in methanol metabolism were further identified through homologous alignment and transcriptome analysis. The methyltransferase cluster along with genes of the carbonyl branch of the Wood−Ljungdahl pathway (WLP) was found to be transcriptionally activated for the assimilation of methanol and CO 2 . To engineer B. methylotrophicum, an efficient electrotransformation protocol and several functional promoters were subsequently developed. Following a systematic investigation of various parameters, the electrotransformation efficiency was increased to 3.2 × 10 3 transformants/μg DNA. The activities of four heterologous promoters including P thl , P araE , P ptb , and P adc were comparatively determined. With these genetic toolkits, transformants overexpressing genes associated with methyltransferase system or butyric acid synthesis were obtained, where methanol consumption was increased by 16.9 and 14%, and butyric acid production was increased by 13.8 and 28.6%, respectively, in methanol and CO 2 medium. These results exhibit the great potential of B. methylotrophicum as a chassis for C1 bioconversion.

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China's average household saving rate is one of the highest in the world. One popular view attributes the high saving rate to fast-rising housing prices and other living costs in China. This article uses simple economic logic to show that rising housing prices and living costs per se cannot explain China's persistently high household saving rate. Although borrowing constraints and demographic changes can help translate housing prices to the aggregate saving rate, quantitative simulations using Chinese data on household income, housing prices, and demographics indicate that rising mortgage costs contribute at most 5 percentage points to the Chinese aggregate household saving rate, given the down payment structure of China's mortgage markets. (JEL D14, D91, E21, I31, R21)