Enhanced biohydrogen production from corn straw by basalt fiber addition

2. Materials and methods 
2.1. Materials 
The mixed photosynthetic bacteria HAU-M1 were screened and 
enriched by the Key Laboratory of Renewable Energy of Ministry of 
Agriculture of Henan Agricultural University (
Lu et al., 2020a
). The 
addition amount of corn straw was 25 ~ 30 g/L, the fermentation 
temperature was set as 30 
℃
, the initial pH value was 7, the light in-
tensity was 3500 ~ 5000 lx, the particle size of straw was 60 mesh and 
the inoculation amount was 20 ~ 30%. The corn straw mainly includes 
35.63% cellulose, 28.62% and 14.83% Lignin (
Supplementary material
, 
Table S1). BF used in experiments was purchased from Zhengzhou 
dengdian basalt Co, Ltd., composing of 35.44% SiO
2
, 14.7% Al
2
O
3
, 
8.21% CaO, 5.93% MgO, 3.65% Na
2
O and others (
Supplementary ma-
terial
, 
Fig.S1
), which determined by X-ray fluorescence spectroscopy. 
2.2. Experimental design 
All batch photo-fermentation hydrogen production (PFHP) experi-
ments were performed in conical flask with effective volume of 180 mL. 
In each bottle, 5 g dried corn straw, 100 mL citric acid-sodium citrate 
buffer (0.5 M), and 150 mg/g cellulase were added firstly. Then, various 
dose of BF (0.5 g/L, 1.0 g/L, 1.5 g/L, 2.0 g/L, and 3.0 g/L) were added 
respectively. A control group was set without BF addition. 
2.3. Analytical methods 
The gas volume was measured by syringe extraction, and the 
hydrogen concentration was detected by Gas chromatograph (GC) 
(Agilent 6820 GC-14B). Dinitrosalicylic acid method was used to 
determine the concentration of reducing sugar in fermentation broth. 
The organic acids contents were determined by the same GC.