Producing Biogas from Rice Straw: Kinetic Analysis and Microbial Community Dynamics

  • PDF / 1,228,662 Bytes
  • 11 Pages / 595.276 x 790.866 pts Page_size
  • 107 Downloads / 200 Views

DOWNLOAD

REPORT


Producing Biogas from Rice Straw: Kinetic Analysis and Microbial Community Dynamics Shiyou Pan 1,2 & Qiangqiang Liu 1 & Chuan Wen 1 & Zhenchong Li 1,2 & Liqin Du 1 & Yutuo Wei 1 Received: 21 September 2020 / Accepted: 23 November 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract Biogas production by anaerobic digestion is an attractive approach to producing clean fuel biomethane and reducing environmental pollution. However, many fluctuations in production occur during a batch digestion period. This study investigated the dynamics of microbial communities involved in biogas production during a 20-day digestion of rice straw (RS) at 35 °C. The results demonstrated roughly consistent trends in biogas and methane production and revealed distinct stages of production. The lowest and peak methane yields were 82 ± 19.9 mL/(L•day) at day 3 and 328.5 ± 0.9 mL/(L•day) at day 8, respectively, whereas most (97.1%) of the methane was produced in the first 14 days of digestion. Ultimately, the biogas potential of RS reached 393.2 ± 13.6 mL/g added volatile solids (CH4% = 57.1%), and the logistic model best fitted actual methane production compared to the modified Gompertz, first-order kinetic, and Cone models. The microbial communities at different critical stages are a clear reflection of the biochemical dynamics in digesters. The bacterial genera Bacteroides and Clostridium_sensu_stricto_1 were the dominant microorganisms at the early stage of digestion, while the archaeal genus Methanosarcina was significantly more abundant at the peak stage of methane production than at other times during the digestion. This study demonstrates the detailed micro- and macro-conditions that exist during the fluctuating and constant digestion of RS, which will benefit industrial applications during the anaerobic digestion of RS. Keywords Methane . Batch anaerobic digestion . Logistic model . Lignocellulose . High-throughput sequencing

Introduction Lignocellulosic biomass is a renewable source of bioenergy (e.g., biomethane) that is widely available, inexpensive, and does not affect food security [1]. Rice straw (RS) is one of the most abundant lignocellulosic waste products from global agriculture, with an annual production of about 0.9 billion tons (dry matter) [2]. However, the incorrect disposal of RS by leaving or burning it in fields causes problems for air quality due to the release of greenhouse gases, especially in China and India [3, 4]. In fact, RS stores more than half of the photosynthetic products from rice crops and is rich in lignocellulose Shiyou Pan and Qiangqiang Liu contributed equally to this work. * Yutuo Wei [email protected] 1

State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China

2

Guangxi Academy of Sciences, Nanning 530007, Guangxi, China

contents (~ 70 wt%) [4–6]. Therefore, RS ce