초록
<P><B>Abstract</B></P><P><B>Aims</B></P><P>Aim of the paper was to assess the feasibility of producing hydrogen as a biofuel by photofermentation of fermented water lettuce (<I>Pistia stratiotes</I> L.) waste biomass, after a nitrogen‐stripping treatment.</P><P><B>Methods and Results</B></P><P>A natural (42OL) and an engineered strain (CGA676, with low‐ammonium sensitivity) of <I>Rhodopseudomonas palustris</I> were used for producing hydrogen. The stripping procedure was highly effective for ammonium removal, with an acceptable selectivity (91% of ammonium was removed; only 14% of total organic acids were lost). Both strains were able to produce hydrogen only in the nitrogen‐stripped substrate. The natural strain <I>R. palustris</I> 42OL showed a higher Biochemical Hydrogen Potential (1224 ml l<SUP>−1</SUP> vs 720 ml l<SUP>−1</SUP>; 50·0 mol m<SUP>−3</SUP> vs 29·4 mol m<SUP>−3</SUP>), but at a lower rate (5·6 ml l<SUP>−1</SUP> h<SUP>−1</SUP> vs 7·3 ml l<SUP>−1</SUP> h<SUP>−1</SUP>; 0·23 mol m<SUP>−3</SUP> h<SUP>−1</SUP> vs 0·29 mol m<SUP>−3</SUP> h<SUP>−1</SUP>) than strain CGA676.</P><P><B>Conclusions</B></P><P>Water lettuce waste biomass can be used for biofuel production, after hydrolization, fermentation and nitrogen stripping.</P><P><B>Significance and Impact of the Study</B></P><P>The investigation on novel, low cost and sustainable biomasses as feedstocks for biofuel production is a priority. Aquatic plants do not compete for arable land. Moreover, water lettuce is a floating and invasive weed, thus its biomass must be harvested when detrimental, and can now be biotransformed in clean hydrogen.</P>