While experts are developing 'greener' alternative fuel sources, a group of undergrads are creating a more natural one.

当专家们还在研发更环保的燃料时，一群在校生已经开始制作一种天然的燃料。

The team is working towards producing a biofuel that uses human and animal excretion, with the hopes of replacing harmful gasoline, diesel¹ and jet fuel that dominate the market.

这个研究小组正在用人和动物的排泄物生产生物燃料。他们希望以此替代目前占据市场主导地位但却有害的汽油、柴油和喷气燃料。

By engineering Bacillus subtilis, researchers are able to break down proteins and transform the left over material into alcohol biofuels and ammonia.

通过对枯草杆菌进行处理，研究者们成功地分离了蛋白质，把排泄物转化为酒精生物燃料和氨气。

The US produces over 1 billion tons of animal and human waste every year, which does nothing but sit in an aerobically² compost giving off harmful emissions³.

美国每年产生超过10亿吨的动物和人类排泄物。它们原本没有任何用处，只能堆在耗氧肥料中释放有害气体。

David Wernick, a PhD candidate who graduated from the University of California, and his colleagues 'were struck by all the waste that is literally⁴ going to waste' and realized the material may have potential as a renewable fuel source, reports the University of California.

大卫·韦尼克是毕业于加州大学的博士生。据加州大学报道，有一天，他和同事们灵机一动，想到这些被浪费掉的排泄物或许可以转化为可再生燃料。

'We're working with anything such as agricultural waste like manure⁵, municipal waste like sewage, plant matter, cellulosic matter and even carbon dioxide out of the atmosphere,' said Wernick in a video discussing the research.

韦尼克在某个视频中讨论了这项研究：“我们正在不断地实验。肥料之类的农业废弃物，污水等城市垃圾，还有植物、纤维素，甚至是空气中的二氧化碳，我们都不放过。”

Wernick explained that the world is dominated by gasoline, diesel and jet fuel as the main transportation⁶ fuels.

韦尼克解释说，汽油、柴油和喷气燃料这些主要的交通燃料目前在世界上占据主导地位。

In 2014, the US consumed 375 million gallons of gasoline every day for the entire year, according to the US Energy Information Administration.

据美国能源情报署数据，2014年，美国每天消耗3.75亿加仑的汽油。

Gasoline isn't just a toxic⁷ and highly flammable liquid it also produces vapors⁸ that pollute our air.

汽油不仅是有毒、易燃液体，它还会释放气体，污染空气。

Burning this liquid releases carbon dioxide into the atmosphere – the biggest culprit of climate change.

燃烧汽油会向大气排放二氧化碳，这也是如今气候变化的罪魁祸首。

And diesel and jet fuel do their part in polluting the air with polyaromatic hydrocarbons⁹ and nitrous oxides.

柴油和航空煤油使用过程中会释放多环芳烃和氮氧化物，同样会污染大气。