Biohydrogen from organic wastes as a clean and environment-friendly energy source: Production pathways, feedstock types, and future prospects.

Microbial fermentation of organic matter under anaerobic conditions is currently the prominent pathway for biohydrogen production. Organic matter present in waste residues is regarded as an economic feedstock for biohydrogen production by dark and photo fermentative bacteria. Agricultural residues, fruit wastes, vegetable wastes, industrial wastewaters, and other livestock residues are some of the organic wastes most commonly used for biohydrogen production due to their higher organic content and biodegradability. Appropriate pretreatments are required to enhance the performance of biohydrogen from complex organic wastes. Biohydrogen production could also be enhanced by optimizing operation conditions and the addition of essential nutrients and nanoparticles. This review describes the pathways of biohydrogen production, discusses the effect of organic waste sources used and microbes involved on biohydrogen production, along with addressing the key parameters, advantages, and difficulties in each biohydrogen production pathway.

Stimulation of Bacillus sp. by lipopeptide biosurfactant for the degradation of aromatic amine 4-Chloroaniline.

This study aims to reveal that the biosurfactant act as a stimulant in aromatic amine 4-Chloroaniline (4-CA) degradation. Isolated degrading strain Bacillus sp. was used for the production of biosurfactant with help of substrate such as engine oil. The surfactant production by the strain was studied by using various screening methods and the results showed best emulsification activity (75%), surface tension reduction activity (28.6 mNm-1) and oil spreading activity (5.9 cm). The obtained surfactant was characterized using Fourier transform infrared spectroscopy (FT-IR), Gas chromatography-Mass Spectrometry (GC-MS), Matrix-Assisted Laser Desorption/ Ionization Time of Flight (MALDI-TOF) which confirmed that the nature of surfactant is lipopeptide. The maximum removal of 4-CA was achieved in different environmental conditions at concentration 100 mg L-1, neutral pH and temperature 30 °C. In the degradation studies, the 4-CA was removed upto 76% by Bacillus sp but in the presence of lipopeptide surfactant, the Bacillus sp removed 4-CA upto 100%. The degraded metabolites were further characterized using High-Pressure Liquid Chromatography (HPLC) and GC-MS. This research indicated that strain Bacillus sp along with the lipopeptide biosurfactant possesses higher potential in the bioremediation of 4-CA compound from the environment.