Japanese biotech ventures promising to make jet fuel from algae and to produce synthetic cartilage are soaring in Tokyo trading as cash pumped into the economy by the central bank cascades into speculative investments.

Five of the 10 best-performing stocks this year traded on Jasdaq, which has lower minimum profit requirements than Japan's main bourse, are biotech firms.

The companies have surged as the Bank of Japan last month voted to double debt-buying to more than ¥7 trillion a month to achieve 2 percent inflation in two years. Prime Minister Shinzo Abe's proposal this month to provide ¥110 billion in support of stem cell research over the next 10 years is also helping the shares.